[DOC] Move old NEWS files to a separate directory

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diff --git a/doc/NEWS/NEWS-1.8.7 b/doc/NEWS/NEWS-1.8.7
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+# -*- rdoc -*-
+
+= NEWS for Ruby 1.8.7
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 1.8.6 release
+
+=== Configuration changes
+
+* default C flags
+
+  Some C compiler flags may be added by default depending on your
+  environment.  Specify optflags=.. and warnflags=.. as necessary to
+  override them.
+
+* vendor_ruby directory
+
+  A new library directory named `vendor_ruby' is introduced in
+  addition to `site_ruby'.  The idea is to separate libraries
+  installed by the package system (`vendor') from manually (`site')
+  installed libraries preventing the former from getting overwritten
+  by the latter, while preserving the user option to override vendor
+  libraries with site libraries. (`site_ruby' takes precedence over
+  `vendor_ruby')
+
+  If you are a package maintainer, make each library package configure
+  the library passing the `--vendor' option to `extconf.rb' so that
+  the library files will get installed under `vendor_ruby'.
+
+  You can change the directory locations using configure options such
+  as `--with-sitedir=DIR' and `--with-vendordir=DIR'.
+
+=== Global constants
+
+* new constants
+
+  * RUBY_COPYRIGHT
+  * RUBY_DESCRIPTION
+
+=== Library updates (outstanding ones only)
+
+* new library
+
+  * securerandom
+
+* builtin classes
+
+  * Array#flatten
+  * Array#flatten!
+
+    Takes an optional argument that determines the level of recursion
+    to flatten.
+
+  * Array#eql?
+  * Array#hash
+  * Array#==
+  * Array#<=>
+
+    Handle recursive data properly.
+
+  * Array#index
+  * Array#rindex
+
+    Use a given block if no argument is given.
+
+  * Array#collect!
+  * Array#map!
+  * Array#each
+  * Array#each_index
+  * Array#reverse_each
+  * Array#reject
+  * Array#reject!
+  * Array#delete_if
+  * Array#select
+
+    Return an enumerator if no block is given.
+
+    Note that #map and #collect still return an array unlike Ruby 1.9
+    to keep compatibility.
+
+  * Array#pop
+  * Array#shift
+
+    Take an optional argument specifying the number of elements to
+    remove.
+
+  * Array#choice
+  * Array#combination
+  * Array#cycle
+  * Array#drop
+  * Array#drop_while
+  * Array#permutation
+  * Array#product
+  * Array#shuffle
+  * Array#shuffle!
+  * Array#take,
+  * Array#take_while
+
+    New methods.
+
+  * Binding#eval
+
+    New method.
+
+  * Dir#each
+  * Dir#foreach
+
+    Return an enumerator if no block is given.
+
+  * Enumerable::Enumerator
+
+    New class for various enumeration defined by the enumerator library.
+
+  * Enumerable#each_slice
+  * Enumerable#each_cons
+  * Object#to_enum
+  * Object#enum_for
+
+    New methods for various enumeration defined by the enumerator library.
+
+  * Enumerable#count
+  * Enumerable#cycle
+  * Enumerable#drop
+  * Enumerable#drop_while
+  * Enumerable#find_index
+  * Enumerable#first
+  * Enumerable#group_by
+  * Enumerable#max_by
+  * Enumerable#min_by
+  * Enumerable#minmax
+  * Enumerable#minmax_by
+  * Enumerable#none?
+  * Enumerable#one?
+  * Enumerable#take
+  * Enumerable#take_while
+
+    New methods.
+
+  * Enumerable#find
+  * Enumerable#find_all
+  * Enumerable#partition
+  * Enumerable#reject
+  * Enumerable#select
+  * Enumerable#sort_by
+
+    Return an enumerator if no block is given.
+
+    Note that #map and #collect still return an array unlike Ruby 1.9
+    to keep compatibility.
+
+  * Enumerable#inject
+
+    Accepts a binary operator instead of a block.
+
+  * Enumerable#reduce
+
+    New alias to #inject.
+
+  * Enumerable#to_a
+
+    Can take optional arguments and pass them to #each.
+
+  * Hash#eql?
+  * Hash#hash
+  * Hash#==
+
+    Handle recursive data properly.
+
+  * Hash#delete_if
+  * Hash#each
+  * Hash#each_key
+  * Hash#each_pair
+  * Hash#each_value
+  * Hash#reject!
+  * Hash#select
+  * ENV.delete_if
+  * ENV.each
+  * ENV.each_key
+  * ENV.each_pair
+  * ENV.each_value
+  * ENV.reject!
+  * ENV.select
+
+    Return an enumerator if no block is given.
+
+  * GC.stress
+  * GC.stress=
+
+    New methods.
+
+  * Integer#ord
+  * Integer#odd?
+  * Integer#even?
+  * Integer#pred
+
+    New methods.
+
+  * Integer#downto
+  * Integer#times
+  * Integer#upto
+
+    Return an enumerator if no block is given.
+
+  * IO#each
+  * IO#each_line
+  * IO#each_byte
+  * IO.foreach
+  * ARGF.each
+  * ARGF.each_line
+  * ARGF.each_byte
+
+    Return an enumerator if no block is given.
+
+  * IO#bytes
+  * IO#chars
+  * IO#each_char
+  * IO#getbyte
+  * IO#lines
+  * IO#readbyte
+  * ARGF.bytes
+  * ARGF.chars
+  * ARGF.each_char
+  * ARGF.getbyte
+  * ARGF.lines
+  * ARGF.readbyte
+
+    New methods.
+
+  * Method#name
+  * Method#owner
+  * Method#receiver
+  * UnboundMethod#name
+  * UnboundMethod#owner
+
+    New methods.
+
+  * Module#class_exec
+  * Module#module_exec
+
+    New methods.
+
+  * Numeric#step
+
+    Return an enumerator if no block is given.
+
+  * Object#instance_exec
+  * Object#tap
+
+    New methods.
+
+  * ObjectSpace.each_object
+
+    Return an enumerator if no block is given.
+
+  * Process.exec implemented.
+
+  * Range#each
+  * Range#step
+
+    Return an enumerator if no block is given.
+
+  * Regexp.union accepts an array of patterns.
+
+  * String#bytes
+
+    New method
+
+  * String#bytesize
+
+    New method, returning the size in bytes. (alias length and size)
+
+  * String#chars
+  * String#each_char
+  * String#lines
+  * String#partition
+  * String#rpartition
+  * String#start_with?
+  * String#end_with?
+
+    New methods.  These are $KCODE aware unlike #index, #rindex and
+    #include?.
+
+  * String#each_byte
+  * String#each
+  * String#each_line
+  * String#gsub(pattern)
+
+    Return an enumerator if no block is given.
+
+  * String#upto
+
+    An optional second argument is added to specify if the last value
+    should be included.
+
+  * StopIteration
+
+    New exception class that causes Kernel#loop to stop iteration when
+    raised.
+
+  * Struct#each
+  * Struct#each_pair
+
+    Return an enumerator if no block is given.
+
+  * Symbol#to_proc
+
+    New method.
+
+  * __method__
+
+    New global function that returns the name of the current method as
+    a Symbol.
+
+* enumerator
+
+  * Enumerator is now a built-in module.  The #next and #rewind
+    methods are implemented using the "generator" library.  Use with
+    care and be aware of the performance loss.
+
+* ipaddr
+
+  * New methods
+    * IPAddr#<=>
+    * IPAddr#succ
+
+      IPAddr objects are now comparable and enumerable having these
+      methods.  This also means that it is possible to have a Range
+      object between two IPAddr objects.
+
+    * IPAddr#to_range
+
+      A new method to create a Range object for the (network) address.
+
+  * Type coercion support
+    * IPAddr#&
+    * IPAddr#|
+    * IPAddr#==
+    * IPAddr#include?
+
+      These methods now accept a string or an integer instead of an
+      IPAddr object as the argument.
+
+* net/smtp
+
+  * Support SSL/TLS.
+
+* openssl
+
+  * New classes
+    * OpenSSL::PKey::EC
+    * OpenSSL::PKey::EC::Group
+    * OpenSSL::PKey::EC::Point
+    * OpenSSL::PKey::PKCS5
+    * OpenSSL::SSL::Session
+
+  * Documentation!
+
+  * Various new methods (see documentation).
+
+  * Remove redundant module namespace in Cipher, Digest, PKCS7, PKCS12.
+    Compatibility classes are provided which will be removed in Ruby 1.9.
+
+* shellwords
+
+  * Add methods for escaping shell-unsafe characters:
+    * Shellwords.join
+    * Shellwords.escape
+    * Array#shelljoin
+    * String#shellescape
+
+  * Add shorthand methods:
+    * Shellwords.split (alias shellwords)
+    * String#shellsplit
+
+* stringio
+
+  * StringIO#getbyte
+  * StringIO#readbyte
+
+    New methods. (aliases for compatibility with 1.9)
+
+  * StringIO#each_char
+  * StringIO#chars
+
+    New methods.
+
+  * StringIO#each
+  * StringIO#each_line
+  * StringIO#each_byte
+
+    Return an enumerator if no block is given.
+
+* tempfile
+
+  * Tempfile.open and Tempfile.new now accept a suffix for the
+    temporary file to be created.  To specify a suffix, pass an array
+    of [basename, suffix] as the first argument.
+
+      Tempfile.open(['image', 'jpg']) { |tempfile| ... }
+
+* tmpdir
+
+  * New method:
+
+    * Dir.mktmpdir
+
+* uri
+
+  * added LDAPS scheme.
+  * Change for RFC3986:
+    * FTP
+      * URI('ftp://example.com/foo').path #=> 'foo'
+      * URI('ftp://example.com/%2Ffoo').path #=> '/foo'
+      * URI::FTP.build([nil, 'example.com', nil, '/foo', 'i']).to_s #=> 'ftp://example.com/%2Ffoo;type=i'
+    * URI merge
+      * URI('http://a/b/c/d;p?q').merge('?y') == URI('http://a/b/c/d;p?y')
+      * URI('http://a/b/c/d;p?q').merge('/./g') == URI('http://a/g')
+      * URI('http://a/b/c/d;p?q').merge('/../g') == URI('http://a/g')
+      * URI('http://a/b/c/d;p?q').merge('../../../g') == URI('http://a/g')
+      * URI('http://a/b/c/d;p?q').merge('../../../../g') == URI('http://a/g')
+
+* rss
+
+  * 0.1.6 -> 0.2.4
+
+  * Fix image module URI
+
+  * Atom support
+
+  * ITunes module support
+
+  * Slash module support
+
+  * content:encoded with RSS 2.0 support
+
+=== Interpreter Implementation
+
+* passing a block to a Proc [experimental]
+
+  This implementation in current shape is known to be buggy/broken,
+  especially with nested block invocation.  Take this as an
+  experimental feature.
+
+* stack trace
+
+  On non-SystemStackError exception, full stack trace is shown.
+
+=== Compatibility issues (excluding feature bug fixes)
+
+* String#slice! had some unintentional bugs and they have been fixed
+  because either they disagreed with documentation or their respective
+  behavior of #slice.  Unfortunately, this causes some
+  incompatibilities in the following (somewhat rare) cases.
+
+  * #slice! no longer expands the array when an out-of-boundary value
+    is given.
+
+      # Ruby 1.8.6
+      a = [1,2]
+      a.slice!(4,0)   #=> nil
+      a               #=> [1,2,nil,nil]
+
+      # Ruby 1.8.7
+      a = [1,2]
+      a.slice!(4,0)   #=> nil
+      a               #=> [1,2]
+
+  * #slice! no longer raises an exception but returns nil when a
+    negative length or out-of-boundary negative position is given.
+
+      # Ruby 1.8.6
+      a = [1,2]
+      a.slice!(1,-1)  #=> (raises IndexError)
+      a.slice!(-5,1)  #=> (raises IndexError)
+
+      # Ruby 1.8.7
+      a = [1,2]
+      a.slice!(1,-1)  #=> nil
+      a.slice!(-5,1)  #=> nil
+
+* String#to_i, String#hex and String#oct no longer accept a sequence
+  of underscores (`__') as part of a number.
+
+    # Ruby 1.8.6
+    '1__0'.to_i     #=> 10
+    '1__0'.to_i(2)  #=> 2  # 0b10
+    '1__0'.oct      #=> 8  # 010
+    '1__0'.hex      #=> 16 # 0x10
+
+    # Ruby 1.8.7
+    '1__0'.to_i     #=> 1
+    '1__0'.to_i(2)  #=> 1
+    '1__0'.oct      #=> 1
+    '1__0'.hex      #=> 1
+
+  The old behavior was inconsistent with Ruby syntax and considered as
+  a bug.
+
+* date
+
+  * Date.parse
+
+    '##.##.##' (where each '#' is a digit) is now taken as 'YY.MM.DD'
+    instead of 'MM.DD.YY'.  While the change may confuse you, you can
+    always use Date.strptime() when you know what you are dealing
+    with.
+
+* REXML
+
+  * REXML::Document.entity_expansion_limit=
+
+    New method to set the entity expansion limit. By default the limit is
+    set to 10000.  See the following URL for details.
+
+    https://www.ruby-lang.org/en/news/2008/08/23/dos-vulnerability-in-rexml/
+
+* stringio
+
+  * StringIO#each_byte
+
+    The return value changed from nil to self.  This is what the
+    document says and the same as each_line() does.
+
+* tempfile
+
+  * The file name format has changed.  No dots are included by default
+    in temporary file names any more.  See above for how to specify a
+    suffix.
+
+* uri
+
+  * See above for details.
+
+== Changes since the 1.8.5 release
+
+=== New platforms/build tools support
+
+* IA64 HP-UX
+
+* Visual C++ 8 SP1
+
+* autoconf 2.6x
+
+=== Global constants
+
+* RUBY_PATCHLEVEL
+
+  New constant since 1.8.5-p1.
+
+=== Library updates (outstanding ones only)
+
+* builtin classes
+
+  * New method: Kernel#instance_variable_defined?
+
+  * New method: Module#class_variable_defined?
+
+  * New feature: Dir::glob() can now take an array of glob patterns.
+
+* date
+
+  * Updated based on date2 4.0.3.
+
+* digest
+
+  * New internal APIs for C and Ruby.
+
+  * Support for autoloading.
+
+      require 'digest'
+
+      # autoloads digest/md5
+      md = Digest::MD5.digest("string")
+
+  * New digest class methods: file
+
+  * New digest instance methods: clone, reset, new, inspect,
+    digest_length (alias size or length), block_length()
+
+  * New library: digest/bubblebabble
+
+  * New function: Digest(name)
+
+* fileutils
+
+  * New option for FileUtils.cp_r(): :remove_destination
+
+* nkf
+
+  * Updated based on nkf as of 2007-01-28.
+
+* thread
+
+  * Replaced with much faster mutex implementation in C.  The former
+    implementation, which is slow but considered to be stable, is
+    available with a configure option `--disable-fastthread'.
+
+* tk
+
+  * Updated Tile extension support based on Tile 0.7.8.
+
+  * Support --without-X11 configure option for non-X11 versions of
+    Tcl/Tk (e.g. Tcl/Tk Aqua).
+
+  * New sample script: irbtkw.rbw -- IRB on Ruby/Tk. It has no trouble
+    about STDIN blocking on Windows.
+
+* webrick
+
+  * New method: WEBrick::Cookie.parse_set_cookies()
+
+=== Compatibility issues (excluding feature bug fixes)
+
+* builtin classes
+
+  * String#intern now raises SecurityError when $SAFE level is greater
+    than zero.
+
+* date
+
+  * Time#to_date and Time#to_datetime are added as private methods.
+    They cause name conflict error in ActiveSupport 1.4.1 and prior,
+    which comes with Rails 1.2.2 and prior.  Updating ActiveSupport
+    and/or Rails to the latest versions fixes the problem.
+
+* digest
+
+  * The constructor does no longer take an initial string to feed.
+    The following examples show how to migrate:
+
+      # Before
+      md = Digest::MD5.new("string")
+      # After (works with any version)
+      md = Digest::MD5.new.update("string")
+
+      # Before
+      hd = Digest::MD5.new("string").hexdigest
+      # After (works with any version)
+      hd = Digest::MD5.hexdigest("string")
+
+  * Digest::Base#==
+
+    * self == string
+
+      Automatic detection between binary digest values and hexadecimal
+      digest values has been dropped.  It is always assumed that a
+      hexadecimal digest value is given for comparison.
+
+    * self == md
+
+      Digest objects are compared by the resulting digest values, not
+      by the exact vector states.
+
+* fileutils
+
+  * A minor implementation change breaks Rake <=0.7.1.
+    Updating Rake to 0.7.2 or higher fixes the problem.
+
+* tk
+
+  * Tk::X_Scrollable (Y_Scrollable) is renamed to Tk::XScrollable
+    (YScrollable). Tk::X_Scrollable (Y_Scrollable) is still available,
+    but it is an alias name.
diff --git a/doc/NEWS/NEWS-1.9.1 b/doc/NEWS/NEWS-1.9.1
new file mode 100644
index 0000000000..fb11026d60
--- /dev/null
+++ b/doc/NEWS/NEWS-1.9.1
@@ -0,0 +1,429 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 1.9.1
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 1.8.7 release
+See doc/NEWS-1.8.7 for changes between 1.8.6 and 1.8.7.
+
+=== Compatibility issues
+
+* language core
+
+    * New syntax and semantics
+          o Block arguments are always local
+          o New semantics for block arguments
+          o defined? and local variables
+          o Parser expects that your source code has only valid byte
+            sequence in some character encoding.  Use magic comments
+            to tell the parser which encoding you use.
+          o New semantics for constant definition in instance_eval
+            or in module_eval.
+
+    * Deprecated syntax
+          o colon (:) instead of "then" in if/unless or case expression.
+          o retry in a loop or an iterator.
+
+* builtin classes and objects
+
+    * Kernel and Object
+          o Kernel#methods and #singleton_methods used to return an
+            array of strings but now they return an array of symbols.
+    * Class and Module
+          o Module#attr works as Module#attr_reader by default.
+	    Optional boolean argument is obsolete.
+          o Module#instance_methods, #private_instance_methods and
+            #public_instance_methods used to return an array of
+            strings but now they return an array of symbols.
+          o Extra subclassing check when binding UnboundMethods
+
+    * Exceptions
+          o Exceptions are equal to each other if they belong to
+            the same class and have the same message and backtrace.
+          o SystemStackError used to be a subclass of StandardError
+            but not it is a direct subclass of Exception.
+          o SecurityError: ditto
+          o Removed Exception#to_str [Ruby2]
+
+    * Enumerable and Enumerator
+          o Enumerable::Enumerator, compatibility alias of Enumerator,
+            is removed.
+          o Enumerable#{map,collect} called without a block returns
+            an enumerator.
+          o Even more builtin and bundled libraries have been made to
+            return an enumerator when called without a block.
+    * Array
+          o Array#nitems was removed (use count {|i| !i.nil?})
+          o Array#choice was removed (use sample)
+          o Array#[m,n] = nil places nil in the array.
+    * Hash
+          o Hash#to_s is equivalent to Hash#inspect
+          o Semantics for Hash#each and Hash#each_pair
+          o Hash#select returns a hash
+          o Hash#key is the new name for #index which has been
+            deprecated.
+          o Hash preserves order.  It enumerates its elements in the
+            order in which the keys are inserted.
+          o Most of the changes in Hash apply to hash like interfaces
+            such as ENV and *DBM.
+    * IO operations
+          o Many methods used to act byte-wise but now some of those act
+            character-wise. You can use alternate byte-wise methods.
+          o IO#getc
+          o Non-blocking IO
+          o Kernel#open takes "t" for newline conversion
+          o Kernel#open takes encoding specified
+          o IO automatically converts byte sequence from a character
+            encodings into another if specified.
+          o StringIO#readpartial
+          o IO.try_convert
+          o IO.binread
+          o IO.copy_stream
+          o IO#binmode?
+          o IO#close_on_exec= and IO#close_on_exec?
+          o Limit input in IO#gets, IO#readline, IO#readlines,
+            IO#each_line, IO#lines, IO.foreach, IO.readlines,
+            StringIO#gets, StringIO#readline, StringIO#each,
+            StringIO#readlines
+          o IO#ungetc, StringIO#ungetc
+          o IO#ungetbyte, StringIO#ungetbyte
+          o IO#internal_encoding, IO#external_encoding,
+            IO#set_encoding
+          o IO.pipe takes encoding option
+          o Directive %u behaves like %d for negative values in
+            printf-style formatting.
+    * File and Dir operations
+          o #to_path is called as necessary in File.path, File.chmod,
+            File.lchmod, File.chown, File.lchown, File.utime,
+            File.unlink, etc..
+          o File.world_readable?
+          o File.world_writable?
+          o Dir.[], Dir.glob
+          o Dir.exist?
+          o Dir.exists?
+    * File::Stat
+          o File::Stat#world_readable?
+          o File::Stat#world_writable?
+    * String
+          o No longer an Enumerable: use each_line/lines for line
+            oriented operation
+          o Encoding-awareness
+              o Character-wise semantics in many methods instead of
+                byte-wise.
+                  o String#[]: Indexing a String with an integer returns a
+                    single character String instead of an integer.
+                  o String#[]=: No longer takes an integer as right
+                    side value.  Note that "str[i] = ?c" because of
+                    the following change.
+                  o ?c is evaluated to a single character string
+                    instead of an integer.
+    * Regexp
+          o Encoding-awareness
+          o Regexp matches only with strings which is encoded in a
+            compatible character encoding to the regexp's.
+          o Regexp#kcode is removed. use Regexp#encoding.
+    * Symbols: restriction on literal symbols
+    * Numeric
+          o Numeric#div always rounds as Integer#div has done.
+          o Numeric#fdiv: ditto.
+    * Integer
+          o Integer(nil) raises TypeError
+    * Fixnum
+          o Fixnum#id2name removed
+          o Fixnum#to_sym removed
+    * Struct
+          o Struct#inspect
+    * Time
+          o New format in Time#to_s
+          o Timezone information preserved on Marshal.dump/load
+    * $SAFE and bound methods
+          o New trusted/untrusted model in addition to
+            tainted/untainted model.
+
+    * Deprecation
+          o $= (global flag for case-sensitiveness on string matching)
+          o Kernel#to_a
+          o Kernel#getc, #gsub, #sub
+          o Kernel#callcc and Continuation now become 'continuation'
+            bundled library.
+          o Object#type
+          o Removed Array and Hash #indices, #indexes
+          o Hash#index
+          o ENV.index
+          o Process::Status#to_int
+          o Numeric#rdiv
+          o Precision is removed.  Don't cry, it will be redesigned
+            and come back in future version.
+          o Symbol#to_int and Symbol#to_i
+          o $KCODE is no longer effective.  Use Encoding related
+            features of each class.
+          o VERSION and friends
+
+* bundled libraries
+
+    * Pathname
+          o No longer has #to_str nor #=~.
+    * time and date
+          o Time.parse and Date.parse interprets slashed numerical dates
+	    as "dd/mm/yyyy".
+    * Readline
+          o If Readline uses libedit, Readline::HISTORY[0] returns the
+            first of the history.
+    * Continuation
+          o as above
+
+    * Deprecation
+          o Complex#image: use Complex#imag
+          o All SSL-related class methods in Net::SMTP
+          o Prime#cache, Prime#primes, Prime#primes_so_far
+          o mailread library: use tmail gem.
+          o cgi-lib library: use cgi.
+          o date2 library: use date.
+          o eregex library
+          o finalize library: use ObjectSpace.define_finalizer if you
+            really need a finalizer. really?
+          o ftools library: use fileutils.
+          o generator library: use Enumerator.
+          o importenv library and Env library
+          o jcode library: use multilingualization support of String
+          o parsedate library
+          o ping library
+          o readbytes library
+          o getopts library and parsearg library: use optparse or
+            getoptlong.
+          o soap, wsdl and xsd libraries: use soap4r gem.
+          o Win32API library: use dl.
+          o dl library: Reimplemented and API changed. use the new
+	    version of dl or ffi gem.
+          o rubyunit library and runit library: use minitest or
+            test/unit. Or use anything you love through RubyGems.
+          o test/unit is reimplemented on top of minitest.  This is
+            not fully compatible with the original.
+
+=== Language core changes
+
+    * New syntax and semantics
+          o Magic comments to declare in which encoding your source
+            code is written
+          o New literal hash syntax and new syntax for hash style
+	    arguments
+          o New syntax for lambdas
+          o .() and calling Procs without #call/#[]
+          o Block in block arguments
+          o Block local variables
+          o Mandatory arguments after optional arguments allowed
+          o Multiple splats allowed
+          o #[] can take splatted arguments, hash style arguments
+            and a block.
+          o New directives in printf-style formatted strings (%).
+          o Newlines allowed before ternary colon operator (:) and
+            method call dot operator (.)
+          o Negative operators such as !, != and !~ are now
+            overloadable
+          o Encoding.default_external and default_internal
+          o __ENCODING__: New pseudo variable to hold the current
+            script's encoding
+
+=== Library updates
+
+* builtin classes and objects
+    * Kernel and Object
+          o BasicObject
+          o Object#=~ returns nil instead of false by default.
+          o Kernel#define_singleton_method
+	  o Kernel#load can load a library from the highest versions
+	    of gems by default.
+    * Class and Module
+          o Module#const_defined?, #const_get and #method_defined?
+            take an optional parameter.
+          o #class_variable_{set,get} are public.
+          o Class of singleton classes
+
+    * Errno::EXXX
+          o All of those are always defined.  Errno::EXXX will be
+            defined as an alias to Errno::NOERROR if your platform
+            does not have one.
+
+    * Binding#eval
+    * Blocks and Procs
+          o Arity of blocks without arguments
+          o proc is now a synonym of Proc.new
+          o Proc#yield
+          o Passing blocks to #[]
+          o Proc#lambda?
+          o Proc#curry
+    * Fiber: coroutines/micro-threads
+    * Thread
+          o Thread.critical and Thread.critical= removed
+          o Thread#exit!, Thread#kill! and Thread#terminate! removed.
+
+    * Enumerable and Enumerator
+          o Enumerator#enum_cons and Enumerator#enum_slice are
+            removed.  Use #each_cons and #each_slice without a block.
+          o Enumerable#each_with_index can take optional arguments
+            and passes them to #each.
+          o Enumerable#each_with_object
+          o Enumerator#with_object
+          o Enumerator.new { ... }
+    * Array
+          o Array#delete returns a deleted element rather than a given
+            object
+          o Array#to_s is equivalent to Array#inspect
+          o Array.try_convert
+          o Array#pack('m0') complies with RFC 4648.
+    * Hash
+          o preserving item insertion order
+          o Hash#default_proc=
+          o Hash#_compare_by_identity and Hash#compare_by_identity?
+          o Hash.try_convert
+          o Hash#assoc
+          o Hash#rassoc
+          o Hash#flatten
+    * Range
+          o Range#cover?
+          o Range#include? iterates over elements and compares the
+            given value with each element unless the range is numeric.
+            Use Range#cover? for the old behavior, i.e. comparison
+            with boundary values.
+          o Range#min, Range#max
+
+    * File and Dir operations
+          o New methods
+    * Process
+          o Process.spawn
+          o Process.daemon
+    * String
+          o String#clear
+          o String#ord
+          o String#getbyte, String#setbyte
+          o String#chars and String#each_char act as character-wise.
+          o String#codepoints, String#each_codepoint
+          o String#unpack with a block
+          o String#hash
+          o String.try_convert
+          o String#encoding
+	  o String#force_encoding, String#encode and String#encode!
+          o String#ascii_only?
+          o String#valid_encoding?
+	  o String#match
+    * Symbol
+          o Zero-length symbols allowed
+          o Symbol#intern
+          o Symbol#encoding
+          o Symbol methods similar to those in String
+    * Regexp
+          o Regexp#=== matches symbols
+          o Regexp.try_convert
+          o Regexp#match
+          o Regexp#fixed_encoding?
+          o Regexp#encoding
+          o Regexp#named_captures
+          o Regexp#names
+    * MatchData
+          o MatchData#names
+          o MatchData#regexp
+    * Encoding
+    * Encoding::Converter
+          o supports conversion between many encodings
+    * Numeric
+          o Numeric#upto, #downto, #times, #step
+          o Numeric#real?, Complex#real?
+          o Numeric#magnitude
+          o Numeric#round
+    * Float
+          o Float#round
+    * Integer
+          o Integer#round
+    * Rational / Complex
+          o They are in the core library now
+    * Math
+          o Math#log takes an optional argument.
+          o Math#log2
+          o Math#cbrt, Math#lgamma, Math#gamma
+    * Time
+          o Time.times removed.  Use Process.times.
+          o Time#sunday?
+          o Time#monday?
+          o Time#tuesday?
+          o Time#wednesday?
+          o Time#thursday?
+          o Time#friday?
+          o Time#saturday?
+          o Time#tv_nsec and Time#nsec
+    * Misc. new methods
+          o RUBY_ENGINE to distinguish between Ruby processor implementation
+          o public_method
+          o public_send
+          o GC.count
+          o ObjectSpace.count_objects
+          o Method#hash, Proc#hash
+          o Method#source_location, UnboundMethod#source_location and
+	    Proc#source_location
+          o __callee__
+          o Elements in $LOAD_PATH and $LOADED_FEATURES are expanded
+
+* bundled libraries
+    * RubyGems
+          o Package management system for Ruby.
+          o Integrated with Ruby's library loader.
+    * Rake
+          o Ruby make. A simple ruby build program with capabilities
+            similar to make.
+    * minitest
+          o Our new testing library which is faster, cleaner and easier
+	    to read than the old test/unit.
+          o You can introduce the old test/unit as testunit gem through
+            RubyGems if you want.
+    * CMath
+          o Complex number version of Math
+    * Prime
+          o Extracted from Mathn and improved. You can easily enumerate
+            prime numbers.
+          o Prime.new is obsolete. Use its class methods.
+    * ripper
+          o Ruby script parser
+    * Readline
+          o Readline.vi_editing_mode?
+          o Readline.emacs_editing_mode?
+          o Readline::HISTORY.clear
+    * Tk
+          o TkXXX widget classes are removed and redefined as aliases of
+            Tk::XXX classes.
+    * RDoc
+          o Updated to version 2.2.2.  See:
+            http://rubyforge.org/frs/shownotes.php?group_id=627&release_id=26434
+    * json
+          o JSON (JavaScript Object Notation) encoder/decoder
+
+* commandline options
+    * -E, --encoding
+    * -U
+    * --enable-gems, --disable-gems
+    * --enable-rubyopt, --disable-rubyopt
+    * long options are allowed in RUBYOPT environment variable.
+
+=== Implementation changes
+
+* Memory Diet
+    * Object Compaction - Object, Array, String, Hash, Struct, Class,
+      Module
+    * st_table compaction (inlining small tables)
+* YARV
+    * Ruby codes are compiled into opcodes before executed.
+    * Native thread
+
+* Platform supports
+    * Support levels
+          (0) Supported
+          (1) Best effort
+          (2) Perhaps
+          (3) Not supported
+    * Dropped
+          o No longer supports djgpp, bcc32, human68k, MacOS 9 or earlier,
+            VMS nor Windows CE.
diff --git a/doc/NEWS/NEWS-1.9.2 b/doc/NEWS/NEWS-1.9.2
new file mode 100644
index 0000000000..430c6cc4f5
--- /dev/null
+++ b/doc/NEWS/NEWS-1.9.2
@@ -0,0 +1,509 @@
+# -*- rdoc -*-
+= NEWS for Ruby 1.9.2
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 1.9.1 release
+=== Library updates (outstanding ones only)
+
+* builtin classes
+
+  * Array
+    * new methods:
+      * Array#keep_if
+      * Array#repeated_combination
+      * Array#repeated_permutation
+      * Array#rotate
+      * Array#rotate!
+      * Array#select!
+      * Array#sort_by!
+
+    * extended method:
+      * Array#{uniq,uniq!,product} can take a block.
+
+  * Complex
+    * new method:
+      * Complex#rationalize
+
+  * Dir
+    * new method:
+      * Dir.home
+
+  * Encoding
+    * new encodings:
+      * Big5
+      * Big5-UAO
+      * ISO-2022-JP-KDDI
+      * SJIS-DoCoMo
+      * SJIS-KDDI
+      * SJIS-SoftBank
+      * UTF8-DoCoMo
+      * UTF8-KDDI
+      * UTF8-SoftBank
+
+    * new method:
+      * ascii_compatible?
+
+  * Enumerable
+    * new methods:
+      * Enumerable#chunk
+      * Enumerable#collect_concat
+      * Enumerable#each_entry
+      * Enumerable#flat_map
+      * Enumerable#slice_before
+
+  * Enumerator
+    * new methods:
+      * Enumerator#peek
+      * Enumerator#next_values
+      * Enumerator#peek_values
+      * Enumerator#feed
+      * StopIteration#result
+
+    * extended method:
+      * #with_index accepts an optional argument that specifies the
+        index number to start with, defaulted to 0.
+
+    * incompatible changes:
+      * #rewind now calls the "rewind" method of the enclosed object
+        if defined.
+      * #next doesn't clear the position at end.
+
+  * ENV
+    * Uses locale's encoding
+    * ENV.[]= raises Errno::{EINVAL,ENOMEM} etc. on failure.
+    * new methods:
+      * ENV.keep_if
+      * ENV.select!
+
+  * Float
+    * new constants:
+      * Float::INFINITY
+      * Float::NAN
+    * new method:
+      * Float#rationalize
+
+  * File
+    * new methods:
+      * File.realpath
+      * File.realdirpath
+
+  * GC::Profiler
+    * new method:
+      * GC::Profiler.total_time
+
+  * Hash
+    * new methods:
+      * Hash#keep_if
+      * Hash#select!
+
+  * IO
+    * new methods:
+      * IO#autoclose=
+      * IO#autoclose?
+      * IO#fdatasync
+      * IO#codepoints
+      * IO#each_codepoint
+
+    * extended method:
+      * IO.pipe can take a block.
+
+    * new modules:
+      * IO::WaitReadable
+      * IO::WaitWritable
+        They are used to extend non-blocking exceptions.
+
+  * Integer
+    * new method:
+      * Integer#rationalize
+
+  * Kernel
+    * new methods:
+      * Kernel#respond_to_missing?
+      * Kernel#singleton_class
+      * Kernel#require_relative
+
+    * extended method:
+      * Kernel#respond_to? can be used to detect methods not implemented.
+        For example, Process.respond_to?(:fork) returns false on Windows.
+
+    * incompatible changes:
+      * Kernel#instance_eval yields the receiver.
+
+      * Kernel#exec
+      * Kernel#spawn
+      * Kernel#system
+      * Kernel#` (`...`)
+        ..etc.
+
+        On Windows, the current directory is no longer implicitly
+        prepended to the default command search path, just like other
+        platforms.
+
+  * MatchData
+    * new method:
+      * MatchData#==
+
+  * Method
+    * new method:
+      * Method#parameters
+
+  * NilClass
+    * new method:
+      * NilClass#rationalize
+
+  * Object
+    * extended methods:
+      * Float() supports hexadecimal floating point format.
+      * printf() supports %a/%A format.
+
+  * Proc
+    * new method:
+      * Proc#parameters
+    * extended method:
+      * Proc#source_location returns location even if receiver is a method
+        defined by attr_reader / attr_writer / attr_accessor.
+
+  * Process
+    * extended method:
+      * Process.spawn accepts [:child, FD] for a redirect target.
+
+  * Random (new class to generate pseudo-random numbers)
+
+  * Rational
+    * new method:
+      * Rational#rationalize
+
+  * String
+    * extended methods:
+      * string[regexp, name] is supported for named capture.
+
+  * Thread
+    * new methods:
+      * Thread#add_trace_func
+      * Thread#set_trace_func
+
+  * Time
+    * extended features:
+      * time_t restriction is removed to represent before 1901 and after 2038.
+        Proleptic Gregorian calendar is used for old dates.
+      * Time.new have optional arguments to specify date with time offset.
+      * Time#getlocal, Time#localtime have optional time offset argument.
+
+    * new methods:
+      * Time#to_r
+      * Time#subsec
+      * Time#round
+
+    * incompatible change:
+      * The year argument of Time.{utc,gm,local,mktime} is now interpreted as
+        the value itself.  For example, Time.utc(99) means the year 99 AD,
+        not 1999 AD.
+
+  * UnboundMethod
+    * new method:
+      * UnboundMethod#parameters
+
+
+* digest
+  * new methods:
+    * Digest::Class.base64digest
+    * Digest::Instance#base64digest
+    * Digest::Instance#base64digest!
+
+  * Digest::HMAC (digest/hmac) has been marked as deprecated because
+    it was unintentional for the experimental library to be included
+    in the final release of 1.9.1.  Please use OpenSSL::HMAC instead.
+
+* rss
+
+  * 0.2.4 -> 0.2.7.
+
+  * RSS::Maker.make
+    * raise an exception not returns nil for invalid feed making.
+    * requires block.
+
+  * RSS::Maker.[]
+    * new method to return maker class.
+
+  * RSS::Maker.supported?(version)
+    * new method to check whether given version is supported.
+
+  * RSS::Maker: item.guid.permanent_link?
+    * new alias of item.guid.isPermaLink
+  * RSS::Maker: item.guid.permanent_link=
+    * new alias of item.guid.isPermaLink=
+
+* DL
+  * Now uses libffi as a backend if available.
+    It means DL works fine on more platforms.
+
+* Fiddle
+  * A lightweight wrapper for libffi.
+
+* YAML
+  * Now uses libyaml as a backend if available.
+    It means YAML library supports new standards for YAML.
+
+* Psych
+  * A wrapper for libyaml.
+
+* JSON
+  * Update to JSON 1.1.9
+
+* REXML
+
+  * REXML::Document.entity_expansion_limit=
+
+    New method to set the entity expansion limit. By default the limit is
+    set to 10000.  See the following URL for details.
+
+    https://www.ruby-lang.org/en/news/2008/08/23/dos-vulnerability-in-rexml/
+
+* RDoc
+
+  * Updated to RDoc 2.5.8
+
+* RubyGems
+
+  * Updated to RubyGems 1.3.7
+
+* logger
+
+  * imported upstream version (logger/1.2.7)
+    * do not raise an exception even if log writing failed.
+    * do not raise ShiftingError if an aged file already exists.
+      (no ShiftingError will be raised from 1.2.7, just warn() instead)
+
+* matrix
+  * API change to adhere strictly to mathematical definitions:
+    * Matrices must now be rectangular.
+    * trace, regular?, singular? are defined only for square matrices
+    * support for empty matrices
+    * all integer matrices now have the right determinant (also an integer)
+
+  * Matrix and Vector include Enumerable.
+
+  * new methods:
+    * Matrix.build
+    * Matrix.empty
+    * Matrix#conj
+    * Matrix#conjugate
+    * Matrix#each
+    * Matrix#each_with_index
+    * Matrix#empty?
+    * Matrix#imag
+    * Matrix#imaginary
+    * Matrix#real
+    * Matrix#real?
+    * Matrix#rect
+    * Matrix#rectangular
+
+* net/http
+  * merged net/https.
+
+* open3
+  * new methods:
+    * Open3.popen2
+    * Open3.popen2e
+    * Open3.capture3
+    * Open3.capture2
+    * Open3.capture2e
+    * Open3.pipeline_rw
+    * Open3.pipeline_r
+    * Open3.pipeline_w
+    * Open3.pipeline_start
+    * Open3.pipeline
+
+* pty
+  * new methods:
+    * PTY.open
+    * PTY.check
+  * deprecated methods:
+    * protect_signal
+    * reset_signal
+
+* openssl
+  * new methods:
+    * OpenSSL::Buffering#read_nonblock
+    * OpenSSL::Buffering#write_nonblock
+    * OpenSSL::SSL::SSLSocket#connect_nonblock
+    * OpenSSL::SSL::SSLSocket#accept_nonblock
+
+* scanf
+  * support %a/%A format.
+
+
+* socket
+
+  * incompatible changes:
+    * Socket#{recvfrom,recvfrom_nonblock,accept,accept_nonblock,sysaccept}
+      returns a sender address as Addrinfo object instead of a binary sockaddr string.
+      Addrinfo#to_s returns the old binary sockaddr string.
+    * BasicSocket#getsockopt returns Socket::Option object instead of a binary string.
+      Socket::Option#to_s returns the old binary string.
+    * Socket.do_not_reverse_lookup is turned on by default now.
+
+  * new class:
+    * Addrinfo
+    * Socket::Option
+    * Socket::AncillaryData
+
+  * new methods:
+    * Socket.ip_address_list
+    * Socket.tcp
+    * Socket.tcp_server_loop
+    * Socket.tcp_server_sockets
+    * Socket.udp_server_sockets
+    * Socket.udp_server_loop_on
+    * Socket.udp_server_loop
+    * Socket.unix
+    * Socket.unix_server_loop
+    * Socket.unix_server_socket
+    * Socket.accept_loop
+    * Socket#ipv6only!
+    * BasicSocket#local_address
+    * BasicSocket#remote_address
+    * BasicSocket#connect_address
+    * BasicSocket#sendmsg
+    * BasicSocket#sendmsg_nonblock
+    * BasicSocket#recvmsg
+    * BasicSocket#recvmsg_nonblock
+    * BasicSocket#getpeereid
+
+  * extended methods:
+    * Socket.new's 3rd argument is optional now.
+    * Socket.pair's 3rd argument is optional now.
+    * Socket.pair and UNIXSocket.pair can take a block.
+    * BasicSocket#send, UDPSocket#send, Socket.getnameinfo, Socket#bind, and
+      Socket#{connect,connect_nonblock} accepts an Addrinfo object as sockaddr.
+    * BasicSocket#getsockopt accepts a Socket::Option object.
+    * Socket.getaddrinfo and IPSocket#{addr,peeraddr} accept an optional
+      argument to turn reverse lookup on/off.
+
+    * constant names can be accepted as well as constant values.
+      i.e. Socket.new(:PF_INET, :SOCK_STREAM, 0)
+      The constant names can be specified without the prefix.
+      i.e. Socket.new(:INET, :STREAM, 0)
+      * protocol/address family
+      * socket type
+      * socket option protocol level
+      * socket option name
+      * shutdown's argument
+
+* stringio
+  * new methods:
+    * StringIO#read_nonblock
+    * StringIO#write_nonblock
+* pathname
+  * new methods:
+    * Pathname#binread
+    * Pathname#realdirpath
+    * Pathname#each_child
+
+  * extended methods:
+    * Pathname#realpath and Pathname#realdirpath takes optional basedir
+      argument.
+
+* Readline
+  * new methods:
+    * Readline.set_screen_size
+    * Readline.get_screen_size
+
+  * extended methods:
+    * Readline.completion_proc= accepts nil.
+      nil means to use default completion proc.
+
+* set
+  * new methods:
+    * Set#keep_if
+    * Set#select!
+
+* time
+  * incompatible changes:
+    * Time.parse raises ArgumentError when no date information.
+
+* thread
+  * extended method:
+    * ConditionVariable#wait takes timeout argument.
+
+* securerandom
+  * new methods:
+    * SecureRandom.urlsafe_base64
+
+* URI
+  * new methods:
+    * URI.encode_www_form
+    * URI.decode_www_form
+    * URI.encode_www_form_component
+    * URI.decode_www_form_component
+  * Obsoleted methods:
+    * URI.decode
+    * URI.encode
+    * URI.escape
+    * URI.unescape
+
+* etc
+  * new methods:
+    * Etc::Passwd.each
+    * Etc::Group.each
+
+* zlib
+  * new methods:
+    * Zlib::GzipFile#path
+    * Zlib.#adler32_combine
+    * Zlib.#crc32_combine
+
+* rbconfig
+  * new methods:
+    * RbConfig.ruby
+
+=== Language changes
+
+* Regexp properties (\p{}) names now ignore underscores, spaces, and case, so
+  \p{ol chiki} is the same as \p{Ol_Chiki}
+* Regexps now support Unicode 5.2 (new characters and scripts)
+* \d, \s, and \w are now ASCII only; use POSIX bracket classes and \p{} for
+  Unicode semantics
+* $: no longer includes the current directory, use require_relative
+* Symbol with an invalid encoding is forbidden to exist.
+
+=== Compilation options
+
+* --program-prefix and --program-suffix no longer act on the shared object
+  names nor paths to libraries.
+
+  use --with-rubylibprefix='${libruby}/${RUBY_INSTALL_NAME}' and
+  --with-soname='${RUBY_INSTALL_NAME}' for the same result as Ruby 1.9.1.
+
+* --with-arch is added for universal binary, instead of
+  --enable-fat-binary option.
+
+=== Compatibility issues (excluding feature bug fixes)
+
+  * Enumerator#rewind
+  * Socket#recvfrom
+  * Socket#recvfrom_nonblock
+  * Socket#accept
+  * Socket#accept_nonblock
+  * Socket#sysaccept
+  * BasicSocket#getsockopt
+  * Time.utc
+  * Time.gm
+  * Time.local
+  * Time.mktime
+  * Time.parse
+  * --program-prefix and --program-suffix
+  * --enable-fat-binary
+  * $:
+
+    See above.
+
+  * Digest::HMAC
+
+    Deprecated.  See above.
diff --git a/doc/NEWS/NEWS-1.9.3 b/doc/NEWS/NEWS-1.9.3
new file mode 100644
index 0000000000..484660f420
--- /dev/null
+++ b/doc/NEWS/NEWS-1.9.3
@@ -0,0 +1,341 @@
+# -*- rdoc -*-
+= NEWS for Ruby 1.9.3
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 1.9.2 release
+=== License
+
+* Ruby's License is changed from a dual license with GPLv2
+  to a dual license with 2-clause BSDL.
+
+=== Known platform dependent issues
+==== OS X Lion
+
+* You have to configure ruby with '--with-gcc=gcc-4.2' if you're using
+  Xcode 4.1, or, if you're using Xcode 4.2, you have to configure ruby
+  with '--with-gcc=clang'.
+
+=== C API updates
+
+* rb_scan_args() is enhanced with support for option hash argument
+  extraction.
+
+* ruby_vm_at_exit() added.  This enables extension libs to hook a VM
+  termination.
+
+* rb_reserved_fd_p() added.  If you want to close all file descriptors,
+  check using this API.  [ruby-core:37759]
+
+=== Library updates (outstanding ones only)
+
+* builtin classes
+
+  * ARGF
+    * new methods:
+      * ARGF.print
+      * ARGF.printf
+      * ARGF.putc
+      * ARGF.puts
+      * ARGF.read_nonblock
+      * ARGF.to_write_io
+      * ARGF.write
+
+  * Array
+    * extended method:
+      * Array#pack supports endian modifiers
+
+  * Bignum
+    * Multiplication algorithm for Bignums with a large number of digits over
+      150 BDIGITs is changed in order to reduce its calculation time.
+      Now such large Bignums are multiplied by using Toom-3 algorithm.
+
+  * Encoding
+    * new encodings:
+      * CP950
+      * CP951
+      * UTF-16
+      * UTF-32
+    * change alias:
+      * SJIS is Windows-31J
+
+  * File
+    * new constant:
+      * File::NULL
+        name of NULL device.
+      * File::DIRECT
+        name of O_DIRECT.
+
+  * IO
+    * extended method:
+      * IO#putc supports multibyte characters
+    * new methods:
+      * IO#advise
+      * IO.write(name, string, [offset] )
+        Write `string` to file `name`.
+        Opposite with File.read.
+      * IO.binwrite(name, string, [offset] )
+        binary version of IO.write.
+
+  * Kernel
+    * move #__id__ to BasicObject.
+    * extended method:
+      * Kernel#rand supports range argument
+
+  * Module
+    * new methods:
+      * Module#private_constant
+      * Module#public_constant
+
+  * Random
+    * extended method:
+      * Random.rand supports range argument
+
+  * String
+    * extended method:
+      * String#unpack supports endian modifiers
+    * new method:
+      * String#prepend
+      * String#byteslice
+
+  * Time
+    * extended method:
+      * Time#strftime supports %:z and %::z.
+
+  * Process
+    * Process#maxgroups and Process#maxgroups= now raise NotImplementedError if
+      the platform don't support supplementary groups concept.
+
+* bigdecimal
+
+  * BigDecimal#power and BigDecimal#** support non-integral exponent.
+
+  * Kernel.BigDecimal and BigDecimal.new now accept instances of Integer,
+    Rational, Float, and BigDecimal.  If you pass a Rational or a Float to
+    them, you must specify the precision to produce the digits of a BigDecimal.
+
+  * The behavior of BigDecimal#coerce with a Rational is changed.  It uses
+    the precision of the receiver BigDecimal to produce the digits of a
+    BigDecimal from the given Rational.
+
+* bigdecimal/util
+
+  * BigDecimal#to_d and Integer#to_d are added.
+
+  * Float#to_d accepts a precision.
+
+  * Rational#to_d raises ArgumentError when passing zero or negative
+    precision.
+
+  * Rational#to_d
+
+    * Zero and an implicit precision is deprecated.
+      This feature is removed at the next release of bigdecimal.
+
+    * A negative precision isn't supported.
+      Be careful it is an incompatible change.
+
+* date
+
+  * Accepts flonum explicitly with limitations.
+    * If the given offset is flonum, DateTime assumes its precision is
+      at most second.
+
+      DateTime.new(2001,2,3,0,0,0,3.0/24) ==
+      DateTime.new(2001,2,3,0,0,0,'+03:00')
+        #=> true
+
+    * If the given operand for -/+ is flonum, DateTime assumes its
+      precision is at most nanosecond.
+
+      DateTime.new(2001,2,3) + 0.5 == DateTime.new(2001,2,3,12)
+        #=> true
+
+    * Precision of offset is always at most second.
+
+      Rational('0.5') == Rational('0.500001')  #=> false
+      DateTime.new(2001,2,3,0,0,0,Rational('0.5')) ==
+      DateTime.new(2001,2,3,0,0,0,Rational('0.500001'))
+        #=> true
+
+  * Ignores long offset and far reform day (with warning).
+
+    * Now accepts only:
+
+      -1<=offset<=1 (-24:00..+24:00)
+      2298874<=start<=2426355 or -/+oo
+        (proleptic Gregorian/Julian mean -/+oo)
+
+  * A method strftime cannot produce huge output (same as Time's one).
+
+    * Even though Date/DateTime can handle far dates, the following causes
+      an exception.
+
+      DateTime.new(1<<10000).strftime('%Y')  # Errno::ERANGE
+
+  * Changed the format of inspect.
+  * Changed the format of marshal (but, can load old dumps).
+
+* io/console
+  * new methods:
+    * IO#noecho {|io| }
+    * IO#echo=
+    * IO#echo?
+    * IO#raw {|io| }
+    * IO#raw!
+    * IO#getch
+    * IO#winsize
+    * IO.console
+
+* json
+  * updated to v1.5.4.
+
+* matrix
+  * new classes:
+    * Matrix::EigenvalueDecomposition
+    * Matrix::LUPDecomposition
+  * new methods:
+    * Matrix#diagonal?
+    * Matrix#eigen
+    * Matrix#eigensystem
+    * Matrix#hermitian?
+    * Matrix#lower_triangular?
+    * Matrix#lup
+    * Matrix#lup_decomposition
+    * Matrix#normal?
+    * Matrix#orthogonal?
+    * Matrix#permutation?
+    * Matrix#round
+    * Matrix#symmetric?
+    * Matrix#unitary?
+    * Matrix#upper_triangular?
+    * Matrix#zero?
+    * Vector#magnitude, #norm
+    * Vector#normalize
+  * extended methods:
+    * Matrix#each and #each_with_index can iterate on a subset of the elements
+    * Matrix#find_index returns [row, column] and can iterate on a subset
+      of the elements
+    * Matrix#** implements Numeric exponents (using the eigensystem)
+    * Matrix.zero can build rectangular matrices
+
+* minitest
+  * Minitest has been updated to version 2.2.2.
+  * For full details, see https://github.com/seattlerb/minitest/blob/master/History.txt
+
+* net/http
+  * SNI (Server Name Indication) supported for HTTPS.
+
+  * Allow to configure to wait server returning '100 continue' response
+    before sending HTTP request body. Set Net::HTTP#continue_timeout AND pass
+    'expect' => '100-continue' to a extra HTTP header.
+
+    For example, the following code sends HTTP header and waits for getting
+    '100 continue' response before sending HTTP request body. When 0.5 [sec]
+    timeout occurs or the server send '100 continue', the client sends HTTP
+    request body.
+      http.continue_timeout = 0.5
+      http.request_post('/continue', 'body=BODY', 'expect' => '100-continue')
+
+  * new method:
+    * Net::HTTPRequest#set_form): Added to support
+      both application/x-www-form-urlencoded and multipart/form-data.
+
+* objspace
+  * new method:
+    * ObjectSpace::memsize_of_all
+
+* openssl
+  * PKey::RSA and PKey::DSA now use the generic X.509 encoding scheme
+    (e.g. used in a X.509 certificate's Subject Public Key Info) when
+    exporting public keys to DER or PEM. Backward compatibility is
+    ensured by (already existing) fallbacks during creation.
+  * OpenSSL::ASN1::Constructive#new and OpenSSL::ASN1::Primitive#new
+    (and the constructors of their sub-classes) will no longer force
+    tagging to be set to :EXPLICIT when tag and/or tag_class are passed
+    as parameters. tagging must be set explicitly.
+  * Support for infinite length encodings via infinite_length attribute.
+  * OpenSSL::PKey.read( file | string [, pwd] ) allows to read arbitrary
+    public/private keys in DER-/PEM-encoded form with an optional password
+    for encrypted PEM encodings.
+  * Add new method OpenSSL::X509::Name#hash_old as a wrapper of
+    X509_NAME_hash_old() defined from OpenSSL 1.0.0. It returns OpenSSL 0.9.8
+    compatible hash value.
+
+* optparse
+  * support for bash/zsh completion.
+
+* Rake
+  * Rake has been upgraded from 0.8.7 to 0.9.2.2.  For full release notes see
+    https://github.com/jimweirich/rake/blob/master/CHANGES
+
+* RDoc
+  * RDoc has been upgraded to version 3.9.4.  For full release notes see
+    http://docs.seattlerb.org/rdoc/History_txt.html
+
+* rexml
+  * Support Ruby native encoding mechanism and iconv dependency is dropped.
+
+* RubyGems
+  * RubyGems has been upgraded to version 1.8.10. For full release notes see
+    http://rubygems.rubyforge.org/rubygems-update/History_txt.html
+
+* stringio
+  * extended method:
+    * StringIO#set_encoding can get 2nd argument and optional hash.
+
+* test/unit
+  * New arguments:
+    * -j N, --jobs=N: Allow run N testcases at once.
+    * --jobs-status: Show status of jobs when parallel running.
+    * --no-retry: Don't retry testcases which failed when parallel running.
+    * --ruby=RUBY: path to ruby for job(worker) process. optional.
+    * --hide-skip: Hide skip messages. You'll see the number of skips at end of
+      test result.
+
+* uri
+  * new methods:
+    * URI::Generic#hostname
+    * URI::Generic#hostname=
+
+* webrick
+  * new method:
+    * WEBrick::HTTPRequest#continue for generating '100 continue' response.
+  * new logging directive:
+    * %{remote}p for remote (client) port number.
+
+* yaml
+  * The default YAML engine is now Psych. You may downgrade to syck by setting
+    YAML::ENGINE.yamler = 'syck'.
+
+* zlib
+  * new methods:
+    * Zlib.deflate
+    * Zlib.inflate
+
+* FileUtils
+  * extended method:
+    * FileUtils#chmod supports symbolic mode argument.
+
+=== Language changes
+
+* Regexps now support Unicode 6.0. (new characters and scripts)
+
+* [experimental] Regexps now support Age property.
+  Unlike Perl, current implementation takes interpretation of the
+  interpretation of UTS #18.
+  http://www.unicode.org/reports/tr18/
+
+* Turning on/off indentation warnings with directives.
+  ("# -*- warn-indent: true -*-" / "# -*- warn-indent: false -*-")
+
+=== Compatibility issues (excluding feature bug fixes)
+
+  * Rational#to_d
+
+    See above.
diff --git a/doc/NEWS/NEWS-2.0.0 b/doc/NEWS/NEWS-2.0.0
new file mode 100644
index 0000000000..e070b19976
--- /dev/null
+++ b/doc/NEWS/NEWS-2.0.0
@@ -0,0 +1,529 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.0.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 1.9.3 release
+
+=== Language changes
+
+* Added keyword arguments.
+
+* Added %i and %I for symbol list creation (similar to %w and %W).
+
+* Default source encoding is changed to UTF-8. (was US-ASCII)
+
+* No warning for unused variables starting with '_'
+
+=== Core classes updates (outstanding ones only)
+
+* ARGF
+  * added method:
+    * added ARGF#codepoints and ARGF#each_codepoint, like the corresponding
+      methods for IO.
+
+* Array
+  * added method:
+    * added Array#bsearch for binary search.
+  * incompatible changes:
+    * random parameter of Array#shuffle! and Array#sample now
+      will be called with one argument, maximum value.
+    * when given Range arguments, Array#values_at now returns nil for each
+      value that is out-of-range.
+
+* Enumerable
+  * added method:
+    * added Enumerable#lazy method for lazy enumeration.
+
+* Enumerator
+  * added method:
+    * added Enumerator#size for lazy size evaluation.
+  * extended method:
+    * Enumerator.new accept an argument for lazy size evaluation.
+  * new class Enumerator::Lazy for lazy enumeration
+
+* ENV
+  * aliased method:
+    * ENV.to_h is a new alias for ENV.to_hash
+
+* Fiber
+  * incompatible changes:
+    * Fiber#resume cannot resume a fiber which invokes "Fiber#transfer".
+
+* File
+  * extended method:
+    * File.fnmatch? now expands braces in the pattern if
+      File::FNM_EXTGLOB option is given.
+
+* GC
+  * improvements:
+    * introduced the bitmap marking which suppresses to copy a memory page
+      with Copy-on-Write.
+    * introduced the non-recursive marking which avoids unexpected stack overflow.
+
+* GC::Profiler
+  * added method:
+    * added GC::Profiler.raw_data which returns raw profile data for GC.
+
+* Hash
+  * added method:
+    * added Hash#to_h as explicit conversion method, like Array#to_a.
+  * extended method:
+    * Hash#default_proc= can be passed nil to clear the default proc.
+
+* IO
+  * deprecated methods:
+    * IO#lines, #bytes, #chars and #codepoints are deprecated.
+
+* Kernel
+  * added method:
+    * added Kernel#Hash conversion method like Array() or Float().
+    * added Kernel#__dir__ which returns the absolute path of the
+      directory of the file from which this method is called.
+    * added Kernel#caller_locations which returns an array of
+      frame information objects.
+  * extended method:
+    * Kernel#warn accepts multiple args in like puts.
+    * Kernel#caller accepts second optional argument `n' which specify
+      required caller size.
+    * Kernel#to_enum and enum_for accept a block for lazy size evaluation.
+  * incompatible changes:
+    * system() and exec() close non-standard file descriptors
+      (The default of :close_others option is changed to true by default.)
+    * respond_to? against a protected method now returns false unless
+      the second argument is true.
+    * __callee__ has returned to the original behavior, and now
+      returns the called name but not the original name in an
+      aliased method.
+    * Kernel#inspect does not call #to_s anymore
+      (it used to call redefined #to_s).
+
+* LoadError
+  * added method:
+    * added LoadError#path method to return the file name that could not be
+      loaded.
+
+* Module
+  * added method:
+    * added Module#prepend which is similar to Module#include,
+      however a method in the prepended module overrides the
+      corresponding method in the prepending module.
+    * added Module.prepended and Module.prepend_features, similar
+      to included and append_features.
+    * added Module#refine, which extends a class or module locally. [experimental]
+  * extended method:
+    * Module#define_method accepts a UnboundMethod from a Module.
+    * Module#const_get accepts a qualified constant string, e.g.
+      Object.const_get("Foo::Bar::Baz")
+
+* Mutex
+  * added method:
+    * added Mutex#owned? which returns the mutex is held by current
+      thread or not. [experimental]
+  * incompatible changes:
+    * Mutex#lock, Mutex#unlock, Mutex#try_lock, Mutex#synchronize
+      and Mutex#sleep are no longer allowed to be used from trap handler
+      and raise a ThreadError in such case.
+    * Mutex#sleep may spurious wakeup. Check after wakeup.
+
+* NilClass
+  * added method:
+    * added nil.to_h which returns {}
+
+* ObjectSpace::WeakMap
+  * new low level class to hold weak references to objects.
+
+* Proc
+  * incompatible change:
+    * removed Proc#== and #eql? so two procs are == only when they are
+      the same object.
+
+* Process
+  * added method:
+    * added getsid for getting session id (unix only).
+
+* Range
+  * added method:
+    * added Range#size for lazy size evaluation.
+    * added Range#bsearch for binary search.
+
+* RubyVM (MRI specific)
+  * added RubyVM::InstructionSequence.of to get the instruction sequence
+    from a method or a block.
+  * added RubyVM::InstructionSequence#path, #absolute_path, #label,
+    #base_label and #first_lineno to retrieve information from where
+    the instruction sequence was defined.
+  * added Environment variables to specify stack usage:
+    * RUBY_THREAD_VM_STACK_SIZE: vm stack size used at thread creation.
+      default: 128KB (32bit CPU) or 256KB (64bit CPU).
+    * RUBY_THREAD_MACHINE_STACK_SIZE: machine stack size used at thread
+      creation. default: 512KB or 1024KB.
+    * RUBY_FIBER_VM_STACK_SIZE: vm stack size used at fiber creation.
+      default: 64KB or 128KB.
+    * RUBY_FIBER_MACHINE_STACK_SIZE: machine stack size used at fiber
+      creation. default: 256KB or 512KB.
+    These variables are checked only at launched time.
+  * added constant DEFAULT_PARAMS to get above default parameters.
+
+* Signal
+  * added method:
+    * added Signal.signame which returns signal name
+
+  * incompatible changes:
+    * Signal.trap raises ArgumentError when :SEGV, :BUS, :ILL, :FPE, :VTALRM
+      are specified.
+
+* String
+  * added method:
+    * added String#b returning a copied string whose encoding is ASCII-8BIT.
+  * change return value:
+    * String#lines now returns an array instead of an enumerator.
+    * String#chars now returns an array instead of an enumerator.
+    * String#codepoints now returns an array instead of an enumerator.
+    * String#bytes now returns an array instead of an enumerator.
+
+* Struct
+  * added method:
+    * added Struct#to_h returning values with keys corresponding to the
+      instance variable names.
+
+* Thread
+  * added method:
+    * added Thread#thread_variable_get for getting thread local variables
+      (these are different than Fiber local variables).
+    * added Thread#thread_variable_set for setting thread local variables.
+    * added Thread#thread_variables for getting a list of the thread local
+      variable keys.
+    * added Thread#thread_variable? for testing to see if a particular thread
+      variable has been set.
+    * added Thread.handle_interrupt as well as instance and singleton methods
+      pending_interrupt? for asynchronous handling of exceptions
+    * added Thread#backtrace_locations which returns similar information of
+      Kernel#caller_locations.
+  * new class Thread::Backtrace::Location to hold backtrace location
+    information. These are returned by Thread#backtrace_locations and
+    Kernel#caller_locations.
+  * incompatible changes:
+    * Thread#join and Thread#value now raises a ThreadError if target thread
+      is the current or main thread.
+
+* Time
+  * change return value:
+    * Time#to_s now returns US-ASCII encoding instead of BINARY.
+
+* TracePoint
+  * new class. This class is replacement of set_trace_func.
+    Easy to use and efficient implementation.
+
+* toplevel
+  * added method:
+    * added main.define_method which defines a global function.
+    * added main.using, which imports refinements into the current file or
+      eval string. [experimental]
+
+=== Core classes compatibility issues (excluding feature bug fixes)
+
+* Array#values_at
+
+  See above.
+
+* String#lines
+* String#chars
+* String#codepoints
+* String#bytes
+
+  These methods no longer return an Enumerator, although passing a
+  block is still supported for backwards compatibility.
+
+  Code like str.lines.with_index(1) { |line, lineno| ... } no longer
+  works because str.lines returns an array.  Replace lines with
+  each_line in such cases.
+
+* IO#lines
+* IO#chars
+* IO#codepoints
+* IO#bytes
+* ARGF#lines
+* ARGF#chars
+* ARGF#bytes
+* StringIO#lines
+* StringIO#chars
+* StringIO#codepoints
+* StringIO#bytes
+* Zlib::GzipReader#lines
+* Zlib::GzipReader#bytes
+
+  These methods are deprecated in favor of each_line, each_byte,
+  each_char and each_codepoint.
+
+* Proc#==
+* Proc#eql?
+
+  These methods were removed. Two procs are == only when they are
+  the same object.
+
+* Fixnum
+* Bignum
+* Float
+
+  Fixnums, Bignums and Floats are frozen.
+
+* Signal.trap
+
+  See above.
+
+* Merge Onigmo.
+  https://github.com/k-takata/Onigmo
+
+* The :close_others option is true by default for system() and exec().
+  Also, the close-on-exec flag is set by default for all new file descriptors.
+  This means file descriptors doesn't inherit to spawned process unless
+  explicitly requested such as system(..., fd=>fd).
+
+* Kernel#respond_to? against a protected method now returns false
+  unless the second argument is true.
+
+* Kernel#respond_to_missing?
+* Kernel#initialize_clone
+* Kernel#initialize_dup
+
+  These methods are now private.
+
+* Thread#join, Thread#value
+
+  See above.
+
+* Mutex#lock, Mutex#unlock, Mutex#try_lock, Mutex#synchronize and Mutex#sleep
+
+  See above.
+
+=== Stdlib updates (outstanding ones only)
+
+* cgi
+  * Add HTML5 tag maker.
+  * CGI#header has been renamed to CGI#http_header and
+    aliased to CGI#header.
+  * When HTML5 tagmaker called, overwrite CGI#header,
+    CGI#header function is to create a <header> element.
+
+* CSV
+  * Removed CSV::dump and CSV::load to protect users from dangerous
+    serialization vulnerability
+
+* iconv
+  * Iconv has been removed. Use String#encode instead.
+
+* io/console
+  * new methods:
+    * added IO#cooked which sets the terminal to cooked mode within the given block.
+    * added IO#cooked! which sets the terminal to cooked.
+  * extended method:
+    * IO#raw, IO#raw!, and IO#getch accept keyword arguments, :min and :time.
+
+* io/wait
+  * new features:
+    * added IO#wait_writable method.
+    * added IO#wait_readable method as alias of IO#wait.
+
+* json
+  * updated to 1.7.7.
+
+* net/http
+  * new features:
+    * Proxies are now automatically detected from the http_proxy environment
+      variable.  See Net::HTTP::new for details.
+    * gzip and deflate compression are now requested for all requests by
+      default.  See Net::HTTP for details.
+    * SSL sessions are now reused across connections for a single instance.
+      This speeds up connection by using a previously negotiated session.
+    * Requests may be created from a URI which sets the request_uri and host
+      header of the request (but does not change the host connected to).
+    * Responses contain the URI requested which allows easier implementation of
+      redirect following.
+  * new methods:
+    * Net::HTTP#local_host
+    * Net::HTTP#local_host=
+    * Net::HTTP#local_port
+    * Net::HTTP#local_port=
+  * extended method:
+    * Net::HTTP#connect uses local_host and local_port if specified.
+
+* net/imap
+  * new methods:
+    * Net::IMAP.default_port
+    * Net::IMAP.default_imap_port
+    * Net::IMAP.default_tls_port
+    * Net::IMAP.default_ssl_port
+    * Net::IMAP.default_imaps_port
+
+* objspace
+  * new method:
+    * ObjectSpace.reachable_objects_from(obj)
+
+* openssl
+  * Consistently raise an error when trying to encode nil values. All instances
+    of OpenSSL::ASN1::Primitive now raise TypeError when calling to_der on an
+    instance whose value is nil. All instances of OpenSSL::ASN1::Constructive
+    raise NoMethodError in the same case. Constructing such values is still
+    permitted.
+  * TLS 1.1 & 1.2 support by setting OpenSSL::SSL::SSLContext#ssl_version to
+    :TLSv1_2, :TLSv1_2_server, :TLSv1_2_client or :TLSv1_1, :TLSv1_1_server
+    :TLSv1_1_client. The version being effectively used can be queried
+    with OpenSSL::SSL#ssl_version. Furthermore, it is also possible to
+    blacklist the new TLS versions with OpenSSL::SSL::OP_NO_TLSv1_1 and
+    OpenSSL::SSL::OP_NO_TLSv1_2.
+  * Added OpenSSL::SSL::SSLContext#renegotiation_cb. A user-defined callback
+    may be set which gets called whenever a new handshake is negotiated. This
+    also allows to programmatically decline (client) renegotiation attempts.
+  * Support for "0/n" splitting of records as BEAST mitigation via
+    OpenSSL::SSL::OP_DONT_INSERT_EMPTY_FRAGMENTS.
+  * The default options for OpenSSL::SSL::SSLContext have changed to
+    OpenSSL::SSL::OP_ALL & ~OpenSSL::SSL::OP_DONT_INSERT_EMPTY_FRAGMENTS
+    instead of OpenSSL::SSL::OP_ALL only. This enables the countermeasure for
+    the BEAST attack by default.
+  * OpenSSL requires passwords for decrypting PEM-encoded files to be at least
+    four characters long. This led to awkward situations where an export with
+    a password with fewer than four characters was possible, but accessing the
+    file afterwards failed. OpenSSL::PKey::RSA, OpenSSL::PKey::DSA and
+    OpenSSL::PKey::EC therefore now enforce the same check when exporting a
+    private key to PEM with a password - it has to be at least four characters
+    long.
+  * SSL/TLS support for the Next Protocol Negotiation extension. Supported
+    with OpenSSL 1.0.1 and higher.
+  * OpenSSL::OPENSSL_FIPS allows client applications to detect whether OpenSSL
+    is FIPS-enabled. OpenSSL.fips_mode= allows turning on and off FIPS mode
+    manually in order to adapt to situations where FIPS mode would be an
+    explicit requirement.
+  * Authenticated Encryption with Associated Data (AEAD) is supported via
+    Cipher#auth_data= and Cipher#auth_tag/Cipher#auth_tag=.
+    Currently (OpenSSL 1.0.1c), only GCM mode is supported.
+
+* ostruct
+  * new methods:
+    * OpenStruct#[], []=
+    * OpenStruct#each_pair
+    * OpenStruct#eql?
+    * OpenStruct#hash
+    * OpenStruct#to_h converts the struct to a hash.
+  * extended method:
+    * OpenStruct.new also accepts an OpenStruct / Struct.
+
+* pathname
+  * extended method:
+    * Pathname#find returns an enumerator if no block is given.
+
+* rake
+  * rake has been updated to version 0.9.5.
+
+    This version is backwards-compatible with previous rake versions and
+    contains many bug fixes.
+
+    See
+    http://rake.rubyforge.org/doc/release_notes/rake-0_9_5_rdoc.html for a list
+    of changes in rake 0.9.3, 0.9.4 and 0.9.5.
+
+* RDoc
+  * RDoc has been updated to version 4.0
+
+    This version is largely backwards-compatible with previous rdoc versions.
+    The most notable change is an update to the ri data format (ri data must
+    be regenerated for gems shared across rdoc versions).  Further API changes
+    are internal and won't affect most users.
+
+    Notable changes include:
+
+    * Page support for ri.  Try `ri ruby:` for a list of pages in ruby or
+      `ri ruby:syntax/literals` for the syntax documentation for literals.
+
+      This also works for gems such as `ri rspec:README` for the rspec gem's
+      README file.
+    * Markdown support.  See ri RDoc::Markdown for details.
+
+    See https://github.com/rdoc/rdoc/blob/master/History.rdoc for a full list
+    of changes in rdoc 4.0.
+
+* resolv
+  * new methods:
+    * Resolv::DNS#timeouts=
+    * Resolv::DNS::Config#timeouts=
+
+* rexml
+  * REXML::Document#write supports Hash arguments.
+  * REXML::Document#write supports new :encoding option. It changes
+    XML document encoding. Without :encoding option, encoding in
+    XML declaration is used for XML document encoding.
+
+* RubyGems
+  * Updated to 2.0.0
+
+    RubyGems 2.0.0 features the following improvements:
+
+    * Improved support for default gems shipping with ruby 2.0.0+
+    * A gem can have arbitrary metadata through Gem::Specification#metadata
+    * `gem search` now defaults to --remote and is anchored like gem list.
+    * Added --document to replace --rdoc and --ri.  Use --no-document to
+      disable documentation, --document=rdoc to only generate rdoc.
+    * Only ri-format documentation is generated by default.
+    * `gem server` uses RDoc::Servlet from RDoc 4.0 to generate HTML
+      documentation.
+
+    For an expanded list of updates and bug fixes see:
+    https://github.com/rubygems/rubygems/blob/master/History.txt
+
+* shellwords
+  * Shellwords#shellescape now stringifies the given object using to_s.
+  * Shellwords#shelljoin accepts non-string objects in the given
+    array, each of which is stringified using to_s.
+
+* stringio
+  * deprecated methods:
+    * StringIO#lines, #bytes, #chars and #codepoints are deprecated.
+
+* syslog
+  * Added Syslog::Logger which provides a Logger API atop Syslog.
+  * Syslog::Priority, Syslog::Level, Syslog::Option and Syslog::Macros
+    are introduced for easy detection of available constants on a
+    running system.
+
+* tmpdir
+  * incompatible changes:
+    * Dir.mktmpdir uses FileUtils.remove_entry instead of
+      FileUtils.remove_entry_secure.  This means that applications should not
+      change the permission of the created temporary directory to make
+      writable from other users.
+
+* yaml
+  * Syck has been removed.  YAML now completely depends on libyaml being
+    installed.
+  * libyaml is now bundled with ruby, for cases where the library is not
+    installed locally.
+
+* zlib
+  * Added streaming support for Zlib::Inflate and Zlib::Deflate.  This allows
+    processing of a stream without the use of large amounts of memory.
+  * Added support for the new deflate strategies Zlib::RLE and Zlib::FIXED.
+  * Zlib streams are now processed without the GVL.  This allows gzip, zlib and
+    deflate streams to be processed in parallel.
+  * deprecated methods:
+    * Zlib::GzipReader#lines and #bytes are deprecated.
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* OpenStruct new methods can conflict with custom attributes named
+  "each_pair", "eql?", "hash" or "to_h".
+
+* Dir.mktmpdir in lib/tmpdir.rb
+
+  See above.
+
+=== C API updates
+
+* NUM2SHORT() and NUM2USHORT() added. They are similar to NUM2INT, but short.
+
+* rb_newobj_of() and NEWOBJ_OF() added. They create a new object of a given class.
diff --git a/doc/NEWS/NEWS-2.1.0 b/doc/NEWS/NEWS-2.1.0
new file mode 100644
index 0000000000..26f2374e94
--- /dev/null
+++ b/doc/NEWS/NEWS-2.1.0
@@ -0,0 +1,376 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.1.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 2.0.0 release
+
+=== Language changes
+
+* Now the default values of keyword arguments can be omitted.  Those
+  "required keyword arguments" need giving explicitly at the call time.
+
+* Added suffixes for integer and float literals: 'r', 'i', and 'ri'.
+  * "42r" and "3.14r" are evaluated as Rational(42, 1) and 3.14.rationalize,
+    respectively.  But exponential form with 'r' suffix like "6.022e+23r" is
+    not accepted because it is misleading.
+  * "42i" and "3.14i" are evaluated as Complex(0, 42) and Complex(0, 3.14),
+    respectively.
+  * "42ri" and "3.14ri" are evaluated as Complex(0, 42r) and Complex(0, 3.14r),
+    respectively.
+
+* def-expr now returns the symbol of its name instead of nil.
+
+=== Core classes updates (outstanding ones only)
+
+* Array
+  * New methods
+    * Array#to_h converts an array of key-value pairs into a Hash.
+
+* Binding
+  * New methods
+    * Binding#local_variable_get(symbol)
+    * Binding#local_variable_set(symbol, obj)
+    * Binding#local_variable_defined?(symbol)
+
+* Enumerable
+  * New methods
+    * Enumerable#to_h converts a list of key-value pairs into a Hash.
+
+* Exception
+  * New methods
+    * Exception#cause provides the previous exception which has been caught
+      at where raising the new exception.
+
+* GC
+  * improvements:
+    * introduced the generational GC a.k.a RGenGC.
+  * added environment variables:
+    * RUBY_GC_HEAP_INIT_SLOTS
+    * RUBY_GC_HEAP_FREE_SLOTS
+    * RUBY_GC_HEAP_GROWTH_FACTOR
+    * RUBY_GC_HEAP_GROWTH_MAX_SLOTS
+    * RUBY_GC_MALLOC_LIMIT_MAX
+    * RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR
+    * RUBY_GC_OLDMALLOC_LIMIT
+    * RUBY_GC_OLDMALLOC_LIMIT_MAX
+    * RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR
+  * obsoleted environment variables:
+    * RUBY_FREE_MIN (Use RUBY_GC_HEAP_FREE_SLOTS instead)
+    * RUBY_HEAP_MIN_SLOTS (Use RUBY_GC_HEAP_INIT_SLOTS instead)
+
+* Integer
+  * New methods
+    * Fixnum#bit_length
+    * Bignum#bit_length
+  * Bignum performance improvement
+    * Use GMP if available.
+      GMP is used only for several operations:
+      multiplication, division, radix conversion, GCD
+
+* IO
+  * extended methods:
+    * IO#seek supports SEEK_DATA and SEEK_HOLE as whence.
+    * IO#seek accepts symbols (:CUR, :END, :SET, :DATA, :HOLE) for 2nd argument.
+    * IO#read_nonblock accepts optional `exception: false` to return symbols
+    * IO#write_nonblock accepts optional `exception: false` to return symbols
+
+* Kernel
+  * New methods:
+    * Kernel#singleton_method
+
+* Module
+  * New methods:
+    * Module#using, which activates refinements of the specified module only
+      in the current class or module definition.
+    * Module#singleton_class? returns true if the receiver is a singleton class
+      or false if it is an ordinary class or module.
+  * extended methods:
+    * Module#refine is no longer experimental.
+    * Module#include and Module#prepend are now public methods.
+
+* Mutex
+  * misc
+    * Mutex#owned? is no longer experimental.
+
+* Numeric
+  * extended methods:
+    * Numeric#step allows the limit argument to be omitted, in which
+      case an infinite sequence of numbers is generated.  Keyword
+      arguments `to` and `by` are introduced for ease of use.
+      `by` can be 0, in which case the same value will be generated
+      indefinitely.
+
+* Process
+  * New methods:
+    * alternative methods to $0/$0=:
+      * Process.argv0() returns the original value of $0.
+      * Process.setproctitle() sets the process title without affecting $0.
+    * Process.clock_gettime
+    * Process.clock_getres
+
+* String
+  * "literal".freeze is now optimized to return the same object
+  * New methods:
+    * String#scrub and String#scrub! verify and fix invalid byte sequence.
+      If you want to use this function with older Ruby,
+      consider to use string-scrub.gem.
+
+* Symbol
+  * All symbols are now frozen.
+
+* pack/unpack (Array/String)
+  * Q! and q! directives for long long type if platform has the type.
+
+* toplevel
+  * extended methods:
+    * main.using is no longer experimental. The method activates refinements
+      in the ancestors of the argument module to support refinement
+      inheritance by Module#include.
+
+=== Core classes compatibility issues (excluding feature bug fixes)
+
+* Hash
+  * incompatible changes:
+    * Hash#reject will return plain Hash object in the future versions, that
+      is the original object's subclass, instance variables, default value,
+      and taintedness will be no longer copied, so now warnings are emitted
+      when called with such Hash.
+
+* IO
+  * incompatible changes:
+    * open ignore internal encoding if external encoding is ASCII-8BIT.
+
+* Kernel#eval, Kernel#instance_eval, and Module#module_eval.
+  * Copies the scope information of the original environment, which means
+    that private, protected, public, and module_function without arguments
+    do not affect the environment outside the eval string.
+    For example, `class Foo; eval "private"; def foo; end; end' doesn't make
+    Foo#foo private.
+
+* Kernel#untrusted?, untrust, and trust
+  * These methods are deprecated and their behavior is the same as tainted?,
+    taint, and untaint, respectively.  If $VERBOSE is true, they show warnings.
+
+* Module#ancestors
+  * The ancestors of a singleton class now include singleton classes,
+    in particular itself.
+
+* Module#define_method and Object#define_singleton_method
+  * Now they return the symbols of the defined methods, not the methods/procs
+    themselves.
+
+* Numeric#quo
+  * Raises TypeError instead of ArgumentError if the receiver doesn't have
+    to_r method.
+
+* Proc
+  * Returning from lambda proc now always exits from the Proc, not from the
+    method where the lambda is created.  Returning from non-lambda proc exits
+    from the method, same as the former behavior.
+
+String
+  * If invalid: :replace is specified for String#encode, replace
+    invalid byte sequence even if the destination encoding equals to
+    the source encoding.
+
+=== Stdlib updates (outstanding ones only)
+
+* CGI::Util
+  * All class methods modulized.
+
+* Digest
+  * extended methods:
+    * Digest::Class.file takes optional arguments for its constructor
+
+* Matrix
+  * Added Vector#cross_product.
+
+* Net::SMTP
+  * Added Net::SMTP#rset to implement the RSET command
+
+* objspace
+  * new method:
+    * ObjectSpace.trace_object_allocations
+    * ObjectSpace.trace_object_allocations_start
+    * ObjectSpace.trace_object_allocations_stop
+    * ObjectSpace.trace_object_allocations_clear
+    * ObjectSpace.allocation_sourcefile
+    * ObjectSpace.allocation_sourceline
+    * ObjectSpace.allocation_class_path
+    * ObjectSpace.allocation_method_id
+    * ObjectSpace.allocation_generation
+    * ObjectSpace.reachable_objects_from_root
+    * ObjectSpace.dump
+    * ObjectSpace.dump_all
+
+* OpenSSL::BN
+  * extended methods:
+    * OpenSSL::BN.new allows Fixnum/Bignum argument.
+
+* open-uri
+  * Support multiple fields with same field name (like Set-Cookie).
+
+* Pathname
+  * New methods:
+    * Pathname#write
+    * Pathname#binwrite
+
+* rake
+  * Updated to 10.1.0.  Major changes include removal of the class namespace,
+    Rake::DSL to hold the rake DSL methods and removal of support for legacy
+    rake features.
+
+    For a complete list of changes since rake 0.9.6 see:
+
+    http://rake.rubyforge.org/doc/release_notes/rake-10_1_0_rdoc.html
+
+    http://rake.rubyforge.org/doc/release_notes/rake-10_0_3_rdoc.html
+
+* RbConfig
+  * New constants:
+    * RbConfig::SIZEOF is added to provide the size of C types.
+
+* RDoc
+  * Updated to 4.1.0.  Major enhancements include a modified default template
+  * and accessibility enhancements.
+
+    For a list of minor enhancements and bug fixes see:
+    https://github.com/rdoc/rdoc/blob/v4.1.0.preview.1/History.rdoc
+
+* Resolv
+  * New methods:
+    * Resolv::DNS.fetch_resource
+  * One-shot multicast DNS support
+  * Support LOC resources
+
+* REXML::Parsers::SAX2Parser
+  * Fixes wrong number of arguments of entitydecl event. Document of the event
+    says "an array of the entity declaration" but implementation passes two
+    or more arguments. It is an implementation bug but it breaks backward
+    compatibility.
+
+* REXML::Parsers::StreamParser
+  * Supports "entity" event.
+
+* REXML::Text
+  * REXML::Text#<< supports method chain like 'text << "XXX" << "YYY"'.
+  * REXML::Text#<< supports not "raw" mode.
+
+* Rinda::RingServer, Rinda::RingFinger
+  * Rinda now supports multicast sockets.  See Rinda::RingServer and
+    Rinda::RingFinger for details.
+
+* RubyGems
+  * Updated to 2.2.0.  Notable new features include:
+
+    * Gemfile or gem.deps.rb support including Gem.file.lock (experimental)
+    * Improved, iterative resolver (compared to RubyGems 2.1 and earlier)
+    * Support for a sharing a GEM_HOME across ruby platforms and versions
+
+    For a complete list of enhancements and bug fixes see:
+    https://github.com/rubygems/rubygems/tree/master/History.txt
+
+* Set
+  * New methods:
+    * Set#intersect?
+    * Set#disjoint?
+
+* Socket
+  * New methods:
+    * Socket.getifaddrs
+
+* StringScanner
+  * extended methods:
+    * StringScanner#[] supports named captures.
+
+* Syslog::Logger
+  * Added facility.
+
+* Tempfile
+  * New methods:
+    * Tempfile.create
+
+* Timeout
+  * The exception to terminate the given block can no longer be rescued
+    inside the block, by default, unless the exception class is given
+    explicitly.
+
+* TSort
+  * New methods:
+    * TSort.tsort
+    * TSort.tsort_each
+    * TSort.strongly_connected_components
+    * TSort.each_strongly_connected_component
+    * TSort.each_strongly_connected_component_from
+
+* WEBrick
+  * The body of a response may now be a StringIO or other IO-like that responds
+    to #readpartial and #read.
+
+* XMLRPC::Client
+  * New methods:
+    * XMLRPC::Client#http. It returns Net::HTTP for the client. Normally,
+      it is not needed. It is useful when you want to change minor HTTP client
+      options. You can change major HTTP client options by XMLRPC::Client
+      methods. You should use XMLRPC::Client methods for changing major
+      HTTP client options instead of XMLRPC::Client#http.
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* Set
+  * incompatible changes:
+    * Set#to_set now returns self instead of generating a copy.
+
+* URI
+  * incompatible changes:
+    * URI.decode_www_form follows current WHATWG URL Standard.
+      It gets encoding argument to specify the character encoding.
+      It now allows loose percent encoded strings, but denies ;-separator.
+    * URI.encode_www_form follows current WHATWG URL Standard.
+      It gets encoding argument to convert before percent encode.
+      UTF-16 strings aren't converted to UTF-8 before percent encode by default.
+
+* curses
+  * Removed.
+    curses is now available as a gem.
+    See https://rubygems.org/gems/curses for details.
+
+=== Built-in global variables compatibility issues
+
+* $SAFE
+  * $SAFE=4 is obsolete.  If $SAFE is set to 4 or larger, an ArgumentError
+    is raised.
+
+=== C API updates
+
+* rb_gc_set_params() is deprecated. This is only used in Ruby internal.
+
+* rb_gc_count() added. This returns the number of times GC occurred.
+
+* rb_gc_stat() added. This allows access to specific GC.stat() values from C
+  without any allocation overhead.
+
+* rb_gc_latest_gc_info() added. This allows access to GC.latest_gc_info().
+
+* rb_postponed_job_register() added. Takes a function callback which is invoked
+  when the VM is in a consistent state, i.e. to perform work from a C signal
+  handler.
+
+* rb_profile_frames() added. Provides low-cost access to the current ruby stack
+  for callstack profiling.
+
+* rb_tracepoint_new() supports new internal events accessible only from C:
+  * RUBY_INTERNAL_EVENT_NEWOBJ
+  * RUBY_INTERNAL_EVENT_FREEOBJ
+  * RUBY_INTERNAL_EVENT_GC_START
+  * RUBY_INTERNAL_EVENT_GC_END_MARK
+  * RUBY_INTERNAL_EVENT_GC_END_SWEEP
+  * Note that you *can not* specify "internal events" with normal events
+    (such as RUBY_EVENT_CALL, RUBY_EVENT_RETURN) simultaneously.
diff --git a/doc/NEWS/NEWS-2.2.0 b/doc/NEWS/NEWS-2.2.0
new file mode 100644
index 0000000000..8b2bd0ba0a
--- /dev/null
+++ b/doc/NEWS/NEWS-2.2.0
@@ -0,0 +1,359 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.2.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file.
+
+== Changes since the 2.1.0 release
+
+=== Language changes
+
+* nil/true/false
+  * nil/true/false objects are frozen. [Feature #8923]
+
+* Hash literal
+  * Symbol key followed by a colon can be quoted. [Feature #4276]
+
+* default argument
+  fixed a very longstanding bug that an optional argument was not
+  accessible in its default value expression.  [Bug #9593]
+
+=== Core classes updates (outstanding ones only)
+
+* Binding
+  * New methods:
+    * Binding#local_variables
+    * Binding#receiver
+
+* Dir
+  * New methods:
+    * Dir#fileno
+
+* Enumerable
+  * New methods:
+    * Enumerable#slice_after
+    * Enumerable#slice_when
+  * Extended methods:
+    * min, min_by, max and max_by supports optional argument to return
+      multiple elements.
+
+* Float
+  * New methods:
+    * Float#next_float
+    * Float#prev_float
+
+* File
+  * New methods:
+    * File.birthtime
+    * File#birthtime
+
+* File::Stat
+  * New methods:
+    * File::Stat#birthtime
+
+* GC
+  * GC.latest_gc_info returns :state to represent current GC status.
+  * Improvements
+    * Introduce incremental marking for major GC. [Feature #10137]
+
+* IO
+  * Improvements
+    * IO#read_nonblock and IO#write_nonblock for pipes on Windows are supported.
+
+* Kernel
+  * New methods:
+    * Kernel#itself
+  * Improvements
+    * Kernel#throw raises UncaughtThrowError, subclass of ArgumentError when
+      there is no corresponding catch block, instead of ArgumentError.
+
+* Process
+  * Extended method:
+    * Process execution methods such as Process.spawn opens the file in write
+      mode for redirect from [:out, :err].
+
+* String
+  * New methods:
+    * String#unicode_normalize
+    * String#unicode_normalize!
+    * String#unicode_normalized?
+
+* Symbol
+  * Improvements
+    * Most symbols which are returned by String#to_sym and
+      String#intern are GC-able.
+
+* Method
+  * New methods:
+    * Method#curry([ arity ]) returns a curried Proc.
+    * Method#super_method returns a Method of superclass, which would be called
+      when super is used.
+
+=== Core classes compatibility issues (excluding feature bug fixes)
+
+* Enumerable
+  * Enumerable#slice_before's state management deprecated.
+  * Enumerable#chunk's state management deprecated.
+
+* GC
+  * incompatible changes:
+    * Rename GC.stat entries. [Feature #9924]
+      See https://docs.google.com/spreadsheets/d/11Ua4uBr6o0k-nORrZLEIIUkHJ9JRzRR0NyZfrhEEnc8/edit?usp=sharing
+
+* Hash
+  * incompatible changes:
+    * Change overriding policy for duplicated key. [Bug #10315]
+      { **hash1, **hash2 } contains values of hash2 for duplicated keys.
+
+* IO
+  * incompatible changes:
+    * When flushing file IO with IO#flush, you cannot assume that the metadata
+      of the file is updated immediately.  On some platforms (especially
+      Windows), it is delayed until the filesystem load is decreased.
+      Use IO#fsync if you want to guarantee updating metadata.
+
+* Math
+  * incompatible changes:
+    * Math.log now raises Math::DomainError instead of returning NaN if the
+      base is less than 0, and returns NaN instead of -infinity if both of
+      two arguments are 0.
+    * Math.atan2 now returns values like as expected by C99 if both two
+      arguments are infinity.
+
+* Proc
+  * incompatible changes:
+    * ArgumentError is no longer raised when lambda Proc is passed as a
+      block, and the number of yielded arguments does not match the formal
+      arguments of the lambda, if just an array is yielded and its length
+      matches.
+
+* Process
+  * Process execution methods such as Process.spawn opens the file in write
+    mode for redirect from [:out, :err].
+    Before Ruby 2.2, it was opened in read mode.
+
+=== Stdlib updates (outstanding ones only)
+
+* Continuation
+  * callcc is obsolete. use Fiber instead.
+
+* Digest
+
+  * Digest() should now be thread-safe.  If you have a problem with
+    regard to on-demand loading under a multi-threaded environment,
+    preload "digest/*" modules on boot or use this method instead of
+    directly referencing Digest::*.
+  * Digest::HMAC has been removed just as previously noticed.
+
+* DL
+  * DL has been removed from stdlib. Please use Fiddle instead!
+
+* Etc
+  * New methods:
+    * Etc.uname
+    * Etc.sysconf
+    * Etc.confstr
+    * IO#pathconf
+    * Etc.nprocessors
+
+* Find, Pathname
+  * Extended methods:
+    * find method accepts "ignore_error" keyword argument.
+
+* Matrix
+  * New methods:
+    * Matrix#first_minor(row, column) returns the submatrix obtained
+      by deleting the specified row and column.
+    * Matrix#cofactor(row, column) returns the (row, column) cofactor
+      which is obtained by multiplying the first minor by (-1)**(row + column).
+    * Matrix#adjugate returns the adjugate of the matrix.
+    * hstack and vstack are new instance and class methods to stack matrices
+      horizontally and vertically.
+    * Matrix#laplace_expansion(row_or_column: num) returns the laplace_expansion
+      along the +num+ -th row or column.
+    * Vector.basis(size:, index:) returns the specified basis vector.
+    * Unary - and + added for Vector and Matrix.
+    * Vector#cross_product generalized to arbitrary dimensions.
+    * Vector#dot and #cross are aliases for #inner_product and #cross_product.
+    * Vector#angle_with returns the angle with its argument
+    * New instance and class method independent? to test linear independence.
+
+* Pathname
+  * Pathname#/ is aliased to Pathname#+.
+  * New methods:
+    * Pathname#birthtime
+
+* Rake
+  * Updated to Rake 10.4.0.  For full release notes see:
+
+    http://docs.seattlerb.org/rake/History_rdoc.html#label-10.4.0
+
+* RubyGems
+  * Updated to RubyGems 2.4.2.  For full release notes see:
+
+    http://docs.seattlerb.org/rubygems/History_txt.html#label-2.4.2+%2F+2014-10-01
+
+* TSort
+  * TSort.tsort_each, TSort.each_strongly_connected_component and
+    TSort.each_strongly_connected_component_from returns an enumerator if
+    no block given.
+
+* XMLRPC
+  * Added new parser class named LibXMLStreamParser.
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* lib/mathn.rb
+  * Show deprecated warning [Feature #10169]
+
+* ext/date/lib/date/format.rb
+  * Removed because it's empty file.
+
+* Digest
+  * Digest::HMAC has finally ceased to exist.  Use OpenSSL::HMAC or an external gem instead.
+
+* time.rb
+  * Time.parse, Time.strptime, Time.rfc2822, Time.xmlschema may produce
+    fixed-offset Time objects.
+    It is happen when usual localtime doesn't preserve the offset from UTC.
+  * Time.httpdate produces always UTC Time object.
+  * Time.strptime raises ArgumentError when no date information.
+
+* lib/rational.rb
+  * Removed because it is deprecated from 2009.
+
+* lib/complex.rb
+  * Removed because it is deprecated from 2009.
+
+* lib/prettyprint.rb
+  * Removed PrettyPrint#first?
+
+* lib/minitest/*.rb
+  * Removed because it conflicts to minitest 5. [Feature #9711]
+
+* lib/test/**/*.rb
+  * Removed because it conflicts to minitest 5, and it was just an wrapper
+    of minitest 4. [Feature #9711]
+
+* lib/uri
+  * support RFC 3986. [Feature #2542]
+
+* GServer
+  * GServer is extracted to gserver gem. It's unmaintain code.
+
+* Logger
+  * Logger::Application is extracted to logger-application gem. It's unmaintain code.
+
+* ObjectSpace (after requiring "objspace")
+  * ObjectSpace.memsize_of(obj) returns a size includes sizeof(RVALUE). [Bug #8984]
+
+* Prime
+  * incompatible changes:
+    * Prime.prime? now returns false for negative numbers. This method
+      should not be used to know the number is composite or not. [Bug #7395]
+
+* Psych
+  * Removed Psych::EngineManager [Bug #8344]
+
+=== Built-in global variables compatibility issues
+
+=== C API updates
+
+* Deprecated APIs removed.  [Feature #9502]
+
+  Check_SafeStr -> SafeStringValue
+  rb_check_safe_str -> SafeStringValue
+  rb_quad_pack -> rb_integer_pack
+  rb_quad_unpack -> rb_integer_unpack
+  rb_read_check : access struct FILE internal. no replacement.
+  rb_struct_iv_get : internal function. no replacement.
+  struct rb_blocking_region_buffer : internal type. no replacement.
+  rb_thread_blocking_region_begin -> rb_thread_call_without_gvl family
+  rb_thread_blocking_region_end -> rb_thread_call_without_gvl family
+  TRAP_BEG -> rb_thread_call_without_gvl family
+  TRAP_END -> rb_thread_call_without_gvl family
+  rb_thread_select -> rb_thread_fd_select
+  struct rb_exec_arg : internal type. no replacement.
+  rb_exec : internal function. no replacement.
+  rb_exec_arg_addopt : internal function. no replacement.
+  rb_exec_arg_fixup : internal function. no replacement.
+  rb_exec_arg_init : internal function. no replacement.
+  rb_exec_err : internal function. no replacement.
+  rb_fork : internal function. no replacement.
+  rb_fork_err : internal function. no replacement.
+  rb_proc_exec_n : internal function. no replacement.
+  rb_run_exec_options : internal function. no replacement.
+  rb_run_exec_options_err : internal function. no replacement.
+  rb_thread_blocking_region -> rb_thread_call_without_gvl family
+  rb_thread_polling -> rb_thread_wait_for
+  rb_big2str0 : internal function. no replacement.
+  rb_big2ulong_pack -> rb_integer_pack
+  rb_gc_set_params : internal function. no replacement.
+  rb_io_mode_flags -> rb_io_modestr_fmode
+  rb_io_modenum_flags -> rb_io_oflags_fmode
+
+* struct RBignum is hidden.  [Feature #6083]
+  Use rb_integer_pack and rb_integer_unpack instead.
+
+* struct RRational is hidden.  [Feature #9513]
+  Use rb_rational_num and rb_rational_den instead.
+
+* rb_big_new and rb_big_resize takes a size_t instead of long.
+
+* rb_num2long returns a long instead of SIGNED_VALUE.
+
+* rb_num2ulong returns an unsigned long instead of VALUE.
+
+* st hash table uses power-of-two sizes for speed [Feature #9425].
+  Lookups are 10-25% faster if using appropriate hash functions.
+  However, weaknesses in hash distribution can no longer be masked
+  by prime number-sized tables, so extensions may need to tweak
+  hash functions to ensure good distribution.
+
+* rb_sym2str() added. This is almost same as `rb_id2str(SYM2ID(sym))`
+  but not pinning a dynamic symbol.
+
+* rb_str_cat_cstr() added. This is the same as `rb_str_cat2()`.
+
+* `rb_str_substr()` and `rb_str_subseq()` will share middle of a string,
+  but not only the end of a string, in the future.  Therefore, result
+  strings may not be NUL-terminated, `StringValueCStr()` is needed
+  calling to obtain a NUL-terminated C string.
+
+* rb_tracepoint_new() supports new internal events accessible only from C:
+  * RUBY_INTERNAL_EVENT_GC_ENTER
+  * RUBY_INTERNAL_EVENT_GC_EXIT
+    r47528
+
+* rb_hash_delete() now does not call the block given to the current method.
+
+* rb_extract_keywords() and rb_get_kwargs() exported.  See README.EXT
+  for details.
+
+=== Build system updates
+
+* jemalloc is optionally supported via `./configure --with-jemalloc`
+  jemalloc may be suitable when system malloc is slow or prone
+  to fragmentation.  [Feature #9113]
+
+=== Implementation changes
+
+* GC
+    * Most symbols which are returned by String#to_sym and
+      String#intern are GC-able [Feature #9634]
+    * Introduce incremental marking for major GC. [Feature #10137]
+    * Enable lazy sweep on GC caused by malloc().
+
+* VM
+    * Use frozen string literals for Hash#[] and Hash#[]=
+    * Fast keyword arguments passing [Feature #10440]
+    * Allow to receive huge splatted array by a rest argument [Feature #10440]
+
+* Process
+    * Process creation methods, such as spawn(), uses vfork() system call.
+      vfork() is faster than fork() when the parent process uses huge memory.
diff --git a/doc/NEWS/NEWS-2.3.0 b/doc/NEWS/NEWS-2.3.0
new file mode 100644
index 0000000000..065515257e
--- /dev/null
+++ b/doc/NEWS/NEWS-2.3.0
@@ -0,0 +1,384 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.3.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file or Redmine
+(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
+
+== Changes since the 2.2.0 release
+
+=== Language changes
+
+* frozen-string-literal pragma:
+
+  * new pragma, frozen-string-literal has been experimentally introduced. [Feature #8976]
+  * besides, --enable/--disable=frozen-string-literal options also have
+    been introduced. [Feature #8976]
+  * command line options --debug or --debug=frozen-string-literal enable
+    additional debugging mode which shows created location with at frozen
+    object error (RuntimeError). [Feature #11725]
+
+* safe navigation operator:
+
+  * new method call syntax, `object&.foo', method #foo is called on
+    `object' if it is not nil. [Feature #11537]
+
+    This is similar to `try!' in Active Support, except:
+    * method name is syntactically required
+          obj.try! {} # valid
+          obj&. {}    # syntax error
+    * arguments are evaluated only if a call is made:
+          obj.try!(:foo, bar())  # bar() is always evaluated
+          obj&.foo(bar())        # bar() is conditionally evaluated
+    * attribute assignment is valid
+          obj&.attr += 1
+
+* the did_you_mean gem:
+
+  * When a NameError or NoMethodError occurs because of a typo in the name,
+    the did_you_mean gem automatically suggests other names similar to the
+    method name.
+
+      "Yuki".starts_with?("Y")
+      # => NoMethodError: undefined method `starts_with?' for "Yuki":String
+      #    Did you mean?  start_with?
+
+* indented here document:
+
+  * new string literal, here document starts with `<<~`.
+    refer doc/syntax/literals.rdoc for more details. [Feature #9098]
+
+=== Core classes updates (outstanding ones only)
+
+* ARGF
+
+  * ARGF.read_nonblock supports `exception: false' like IO#read_nonblock. [Feature #11358]
+
+* Array
+
+  * Array#bsearch_index [Feature #10730]
+  * Array#dig [Feature #11643]
+
+* Comparable
+
+  * Comparable#== no longer rescues exceptions [Feature #7688]
+
+* Encoding
+
+  * new Encoding::IBM037 (alias ebcdic-cp-us; dummy)
+
+* Enumerable
+
+  * Enumerable#grep_v is added as inverse version of Enumerable#grep. [Feature #11049]
+  * Enumerable#chunk_while [Feature #10769]
+
+* Enumerator::Lazy
+
+  * Enumerator::Lazy#grep_v [Feature #11773]
+
+* File
+
+  * File.mkfifo [Feature #11536]
+  * Add File::TMPFILE corresponding to O_TMPFILE
+
+* Hash
+
+  * Hash#fetch_values [Feature #10017]
+  * Hash#dig [Feature #11643]
+  * Hash#<=, Hash#<, Hash#>=, Hash#> [Feature #10984]
+  * Hash#to_proc [Feature #11653]
+
+* IO
+
+  * new mode flag File::SHARE_DELETE is available.
+    this flag means to permit deleting opened file on Windows, but currently
+    this affect only files opened as binary.  [Feature #11218]
+
+  * new option parameter `flags' is added.
+    this parameter is bitwise-ORed to oflags generated by normal mode argument. [Feature #11253]
+
+  * IO#advise no longer raises Errno::ENOSYS in cases where it was
+    detected at build time but not available at runtime.  [Feature #11806]
+
+* Kernel
+
+  * Kernel#loop, when stopped by a StopIteration exception, returns
+    what the enumerator has returned instead of nil. [Feature #11498]
+
+* Module
+  * Module#deprecate_constant [Feature #11398]
+
+* NameError
+  * NameError#receiver is added to take the receiver object. [Feature #10881]
+
+* Numeric
+
+  * Numeric#positive? and Numeric#negative? are added, which return
+    true when the receiver is positive and negative respectively. [Feature #11151]
+
+* Proc
+
+  * Proc#call (and also #[], #===, #yield) are optimized.
+    Backtrace doesn't show each method (show block lines directly).
+    TracePoint also ignores these calls. [Feature #11569]
+
+* Queue (Thread::Queue)
+
+  * Queue#close is added to notice a termination. [Feature #10600]
+
+* Regexp/String: Updated Unicode version from 7.0.0 to 8.0.0
+
+* RubyVM::InstructionSequence
+  * add the following methods as a primitive tool of iseq loader.
+    See sample/iseq_loader.rb for usage.
+    Note that loader does not have verifier so it is easy to cause
+    critical problem by loading modified/broken binary data.
+    See [Feature #11788] for more details. (experimental feature)
+    * RubyVM::InstructionSequence#to_binary(extra_data = nil)
+    * RubyVM::InstructionSequence.load_from_binary(binary)
+    * RubyVM::InstructionSequence.load_from_binary_extra_data(binary)
+
+* String
+
+  * String#+@ and String#-@ are added to get mutable/frozen strings. [Feature #11782]
+
+  * String.new now accepts new option parameter `encoding'. [Feature #11785]
+
+* Struct
+  * Struct#dig [Feature #11688]
+
+* Thread
+  * Thread#name, Thread#name= are added to handle thread names [Feature #11251]
+
+=== Core classes compatibility issues (excluding feature bug fixes)
+
+* Array
+  * Array#select!, Array#keep_if, Array#reject!, and Array#delete_if
+    no longer changes the receiver array instantly every time the
+    block is called.  [Feature #10714]
+
+  * Array#flatten and Array#flatten! no longer try to call #to_ary
+    method on elements beyond the given level.  [Bug #10748]
+
+  * Array#inspect doesn't raise error even if its content returns
+    a string which is not compatible with Encoding.default_external
+    as inspected result. [Feature #11801]
+
+* Enumerable
+  * Enumerable#chunk and Enumerable#slice_before no longer takes the
+    initial_state argument.  [Feature #10958]
+    Use a local variable instead to maintain a state.
+
+* File::Stat
+  * On Windows File::Stat#ino always returned 0, but now returns
+    BY_HANDLE_FILE_INFORMATION.nFileIndexHigh/Low.  [Feature #11216]
+
+* Hash
+  * Hash#inspect doesn't raise error even if its content returns
+    a string which is not compatible with Encoding.default_external
+    as inspected result. [Feature #11801]
+
+* IO
+  * IO#close doesn't raise when the IO object is closed.  [Feature #10718]
+  * IO#each_codepoint raises an exception at incomplete character
+    before EOF when conversion takes place.  [Bug #11444]
+
+* Module
+  * Module#define_method and Object.define_singleton_method now
+    require method body, Proc, Method, or a block, and raise
+    ArgumentError if no block is given directly.  [Bug #11283]
+
+* pack/unpack (Array/String)
+  * j and J directives for pointer width integer type.  [Feature #11215]
+
+
+=== Stdlib updates (outstanding ones only)
+
+* Logger
+
+  * Logger#level= now supports symbol and string levels such as :debug, :info,
+    :warn, :error, :fatal (case insensitive) [Feature #11695]
+  * Logger#reopen is added to reopen a log device. [Feature #11696]
+
+* io/wait
+  * IO#wait_readable no longer checks FIONREAD, it may be used for
+    non-bytestream IO such as listen sockets.
+
+* Net::FTP
+  * Net::FTP#mlst is added.
+  * Net::FTP#mlsd is added.
+
+* nkf
+  * Merge nkf 2.1.4.
+
+* ObjectSpace (objspace)
+  * ObjectSpace.count_symbols is added.
+  * ObjectSpace.count_imemo_objects is added.
+  * ObjectSpace.internal_class_of is added.
+  * ObjectSpace.internal_super_of is added.
+
+* OpenSSL
+  * OpenSSL::SSL::SSLSocket#accept_nonblock and
+    OpenSSL::SSL::SSLSocket#connect_nonblock supports `exception: false`. [Feature #10532]
+
+* Pathname
+  * Pathname#descend and Pathname#ascend supported blockless form. [Feature #11052]
+
+* Socket
+  * Socket#connect_nonblock, Socket#accept_nonblock,
+    TCPServer#accept_nonblock, UNIXServer#accept_nonblock,
+    BasicSocket#recv_nonblock, BasicSocket#recvmsg_nonblock,
+    BasicSocket#sendmsg_nonblock all support `exception: false` to return
+    :wait_readable or :wait_writable symbols instead of raising
+    IO::WaitReadable or IO::WaitWritable exceptions [Feature #10532] [Feature #11229]
+  * BasicSocket#recv and BasicSocket#recv_nonblock allow an output
+    String buffer argument like IO#read and IO#read_nonblock to reduce
+    GC overhead [Feature #11242]
+
+* StringIO
+  * In read-only mode, StringIO#set_encoding no longer sets the encoding
+    of its buffer string.  Setting the encoding of the string directly
+    without StringIO#set_encoding may cause unpredictable behavior now. [Bug #11827]
+
+* timeout
+  * Object#timeout is now warned as deprecated when called.
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* ext/coverage/coverage.c
+  * Coverage.peek_result: new method to allow coverage to be captured without
+    stopping the coverage tool.  [Feature #10816]
+
+* Fiddle
+  * Fiddle::Function#call releases the GVL.  [Feature #11607]
+
+* io-console
+  * Update to io-console 0.4.5, and change the license to BSD 2-clause
+    "Simplified" License.
+
+* lib/base64.rb
+  * Base64.urlsafe_encode64: added a "padding" option to suppress
+    the padding character ("=").  [Feature #10740]
+  * Base64.urlsafe_decode64: now it accepts not only correctly-padded
+    input but also unpadded input.  [Feature #10740]
+
+* lib/drb/drb.rb
+  * removed unused argument. https://github.com/ruby/ruby/pull/515
+
+* lib/matrix.rb
+  * Add Vector#round. https://github.com/ruby/ruby/pull/802
+
+* lib/webrick/utils.rb
+  * removed unused argument. https://github.com/ruby/ruby/pull/356
+
+* Net::FTP
+  * Connections are in passive mode per default now.  The default mode can
+    be changed by Net::FTP.default_passive=.  [Feature #11612]
+
+* Net::HTTP
+  * default value of Net::HTTP#open_timeout is now 60 (was nil).
+
+* Net::Telnet
+  * Net::Telnet is extracted to net-telnet gem. It's unmaintain code. [Feature #11083]
+
+* Psych
+  * Updated to Psych 2.0.17
+
+* Rake
+  * Rake is removed from stdlib.  [Feature #11025]
+
+* RDoc
+  * Updated to RDoc 4.2.1.  For full release notes see:
+
+    https://github.com/rdoc/rdoc/blob/master/History.rdoc#421--2015-12-22
+
+* RubyGems
+  * Updated to RubyGems 2.5.1.  For full release notes see:
+
+    http://docs.seattlerb.org/rubygems/History_txt.html#label-2.5.0+-2F+2015-11-03
+    and
+    http://docs.seattlerb.org/rubygems/History_txt.html#label-2.5.1+-2F+2015-12-10
+
+=== Built-in global variables compatibility issues
+
+* $SAFE
+  * $SAFE=2 and $SAFE=3 are obsolete.  If $SAFE is set to 2 or larger,
+    an ArgumentError is raised.  [Feature #5455]
+
+=== C API updates
+
+* rb_define_class_id_under() now raises a TypeError exception when the
+  class is already defined but its superclass does not match the given
+  superclass, as well as definitions in ruby level.
+
+* rb_timespec_now() is added to fetch current datetime as struct timespec. [Feature #11558]
+
+* rb_time_timespec_new() is added to create a time object with epoch,
+  nanosecond, and UTC/localtime/time offset arguments.  [Feature #11558]
+
+* rb_autoload() deprecated, use rb_funcall() instead.  [Feature #11664]
+
+* rb_compile_error_with_enc(), rb_compile_error(), and rb_compile_bug()
+  deprecated.  these functions are exposed but only for internal use.
+  external libraries should not use them.
+
+=== Supported platform changes
+
+* OS/2 is no longer supported
+
+* BeOS is no longer supported
+
+* Borland-C is no longer supported
+
+* Haiku now stable and best effort
+
+=== Implementation improvements
+
+* Optimize Proc#call to eliminate method frame construction. [Feature #11569]
+
+* Reconsidering method entry data structure. [Bug #11278]
+
+* Introducing new table data structure for ID keys tables used by
+  method table and so on. New table structure is simple and fast
+  than st_table. [Feature #11420]
+
+* Machine code level tuning for object allocation and method calling
+  code. r52099, r52254
+
+* RubyVM::InstructionSequence is extended for future improvement. [Feature #11788]
+
+* Case dispatch is now optimized for all special constant literals
+  including nil, true, and false.  Previously, only literal strings,
+  symbols, integers and floats compiled to optimized case dispatch. [Feature #11769]
+
+* Instance variables on non-pure Ruby classes (T_DATA, T_FILE,
+  etc..) is less expensive to store than before. [Feature #11170]
+
+* All accesses to members of big Struct objects are performed in
+  constant-time.  Previously, Struct elements beyond the first 10
+  elements used a linear scan. [Feature #10585]
+
+* The Set class got several speed up. [Misc #10754], [r52591]
+
+* Socket and I/O-related improvements
+
+  * Calling overhead of most of new keyword-using I/O methods in
+    [Feature #11229] is reduced by avoiding the inefficient C API
+    to parse keywords.  [Feature #11339]
+
+  * The standard library is updated to use the improved
+    exception-free non-blocking I/O from [Feature #11229].
+    This has the additional benefit of quieter $DEBUG output in
+    addition to reducing expensive exceptions. [Feature #11044]
+
+  * (Linux-only) waiting on a single FD anywhere in the stdlib no longer
+    uses select(2), making it immune to slowdowns with high-numbered
+    FDs. [Feature #11081] [Feature #11377]
+
+* CGI.escapeHTML is optimized with C extension.
+  https://github.com/ruby/ruby/pull/1164
diff --git a/doc/NEWS/NEWS-2.4.0 b/doc/NEWS/NEWS-2.4.0
new file mode 100644
index 0000000000..8a02f03809
--- /dev/null
+++ b/doc/NEWS/NEWS-2.4.0
@@ -0,0 +1,399 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.4.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file or Redmine
+(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
+
+== Changes since the 2.3.0 release
+
+=== Language changes
+
+* Multiple assignment in conditional expression is now allowed.  [Feature #10617]
+
+* Refinements is enabled at method by Symbol#to_proc.  [Feature #9451]
+
+* Refinements is enabled with Kernel#send and BasicObject#__send__.  [Feature #11476]
+
+* Rescue modifier now applicable to method arguments.  [Feature #12686]
+
+* Toplevel return is now allowed.  [Feature #4840]
+
+=== Core classes updates (outstanding ones only)
+
+* Array
+
+  * Array#concat [Feature #12333]
+
+    Now takes multiple arguments.
+
+  * Array#max and Array#min.  [Feature #12172]
+
+    This may cause a tiny incompatibility: if you redefine
+    Enumerable#max and call max to an Array, your redefinition will be
+    now ignored.  You should also redefine Array#max.
+
+  * Array#pack [Feature #12754]
+
+    Now takes optional argument `buffer:' to reuse already allocated buffer.
+
+  * Array#sum  [Feature #12217]
+
+    This is different from Enumerable#sum in that Array#sum doesn't depend on
+    the definition of each method.
+
+* Comparable
+
+  * Comparable#clamp.  [Feature #10594]
+
+* Dir
+
+  * Dir.empty?.  [Feature #10121]
+
+* Enumerable
+
+  * Enumerable#chunk called without a block now return an Enumerator  [Feature #2172]
+  * Enumerable#sum  [Feature #12217]
+  * Enumerable#uniq  [Feature #11090]
+
+* Enumerator::Lazy
+
+  * Enumerator::Lazy#chunk_while  [GH-1186]
+  * Enumerator::Lazy#uniq  [Feature #11090]
+
+* File
+
+  * File.empty?.  [Feature #9969]
+
+* Float
+
+  * Float#ceil, Float#floor, and Float#truncate now take an optional
+    digits, as well as Float#round.  [Feature #12245]
+
+  * Float#round now takes an optional keyword argument, half option, and
+    the default behavior is round-up.  [Bug #12548] [Bug #12958]
+    half option can be one of :even, :up, and :down.  [Feature #12953]
+
+* Hash
+
+  * Hash#compact and Hash#compact!  [Feature #11818]
+  * Hash#transform_values and Hash#transform_values!  [Feature #12512]
+
+* Integer
+
+  * Fixnum and Bignum are unified into Integer  [Feature #12005]
+
+  * Integer#ceil, Integer#floor, and Integer#truncate now take an optional
+    digits, as well as Integer#round.  [Feature #12245]
+
+  * Integer#digits for extracting columns of place-value notation [Feature #12447]
+
+  * Integer#round now takes an optional keyword argument, half option, and the
+    default behavior is round-up now.  [Bug #12548] [Bug #12958]
+
+    half option can be one of :even, :up, and :down.  [Feature #12953]
+
+* IO
+
+  * IO#gets, IO#readline, IO#each_line, IO#readlines, IO.foreach now takes
+    an optional keyword argument, chomp flag.  [Feature #12553]
+
+* Kernel
+
+  * Kernel#clone now takes an optional keyword argument, freeze flag.  [Feature #12300]
+
+* MatchData
+
+  * MatchData#named_captures [Feature #11999]
+  * MatchData#values_at supports named captures [Feature #9179]
+
+* Module
+
+  * Module#refine accepts a module as the argument now. [Feature #12534]
+  * Module.used_modules [Feature #7418]
+
+* Numeric
+
+  * Numeric#finite?, Numeric#infinite? [Feature #12039]
+
+* Process
+
+  * Support CLOCK_MONOTONIC_RAW_APPROX, CLOCK_UPTIME_RAW, and
+    CLOCK_UPTIME_RAW_APPROX which are introduced by macOS 10.12.
+
+* Rational
+
+  * Rational#round now takes an optional keyword argument, half option, and
+    the default behavior is round-up now.  [Bug #12548] [Bug #12958]
+    half option can be one of :even, :up, and :down.  [Feature #12953]
+
+* Regexp
+
+  * meta character \X matches Unicode 9.0 characters with some workarounds
+    for UTR #51 Unicode Emoji, Version 4.0 emoji zwj sequences.
+
+  * Regexp#match? [Feature #8110]
+
+    This returns bool and doesn't save backref.
+
+  * Update to Onigmo 6.0.0.
+
+* Regexp/String: Update Unicode version from 8.0.0 to 9.0.0 [Feature #12513]
+
+* RubyVM::Env
+
+  * RubyVM::Env was removed.
+
+* String
+
+  * String#casecmp? [Feature #12786]
+
+  * String#concat, String#prepend [Feature #12333]
+
+    Now takes multiple arguments.
+
+  * String#each_line, String#lines now takes an optional keyword argument,
+    chomp flag.  [Feature #12553]
+
+  * String#match? [Feature #12898]
+
+  * String#unpack1 [Feature #12752]
+
+  * String#upcase, String#downcase, String#capitalize, String#swapcase and
+    their bang variants work for all of Unicode, and are no longer limited
+    to ASCII. Supported encodings are UTF-8, UTF-16BE/LE, UTF-32BE/LE, and
+    ISO-8859-1~16. Variations are available with options. See the documentation
+    of String#downcase for details. [Feature #10085]
+
+  * String.new(capacity: size) [Feature #12024]
+
+* StringIO
+
+  * StringIO#gets, StringIO#readline, StringIO#each_line, StringIO#readlines now takes
+    an optional keyword argument, chomp flag.  [Feature #12553]
+
+* Symbol
+
+  * Symbol#casecmp? [Feature #12786]
+
+  * Symbol#match now returns MatchData.  [Bug #11991]
+
+  * Symbol#match? [Feature #12898]
+
+  * Symbol#upcase, Symbol#downcase, Symbol#capitalize, and Symbol#swapcase now
+    work for all of Unicode. See the documentation of String#downcase
+    for details. [Feature #10085]
+
+* Thread
+
+  * Thread#report_on_exception and Thread.report_on_exception [Feature #6647]
+
+* TracePoint
+
+  * TracePoint#callee_id [Feature #12747]
+
+* Warning
+
+  * New module named Warning is introduced.  By default it has only
+    one singleton method, named warn.  This makes it possible for
+    3rd-party libraries to control the way warnings are handled. [Feature #12299]
+
+=== Stdlib updates (outstanding ones only)
+
+* CGI
+
+  * Don't allow , as a separator [Bug #12791]
+
+* CSV
+
+  * Add a liberal_parsing option. [Feature #11839]
+
+* IPAddr
+
+  * IPAddr#== and IPAddr#<=> no longer raise an exception if coercion fails. [Bug #12799]
+
+* IRB
+
+  * Binding#irb: Start a REPL session like `binding.pry` at r56624.
+
+* Logger
+
+  * Allow specifying logger parameters in constructor such
+    as level, progname, datetime_format, formatter. [Feature #12224]
+  * Add shift_period_suffix option. [Feature #10772]
+
+* Net::HTTP
+
+  * New method: Net::HTTP.post [Feature #12375]
+
+* Net::FTP
+
+  * Support TLS (RFC 4217).
+  * Support hash style options for Net::FTP.new.
+  * Add a new optional argument pathname to Net::FTP#status.
+    Contributed by soleboxy. [GH-1478] [Feature #12965]
+
+* OpenSSL
+
+  * Includes Ruby/OpenSSL 2.0. OpenSSL has been extracted as a Gem and is
+    maintained at a separate repository now: https://github.com/ruby/openssl.
+    It still remains as a 'default gem'.  [Feature #9612]
+    Refer to ext/openssl/History.md for the full release note.
+
+* optparse
+
+  * Add an into option. [Feature #11191]
+
+* pathname
+
+  * New method: Pathname#empty? [Feature #12596]
+
+* Readline
+
+  * Readline.quoting_detection_proc and Readline.quoting_detection_proc= [Feature #12659]
+
+* REXML
+
+  * REXML::Element#[]: If String or Symbol is specified, attribute
+    value is returned. Otherwise, Nth child is returned. This is
+    backward compatible change.
+
+* set
+
+  * New methods: Set#compare_by_identity and Set#compare_by_identity?. [Feature #12210]
+
+* WEBrick
+
+  * Don't allow , as a separator [Bug #12791]
+
+=== Compatibility issues (excluding feature bug fixes)
+
+* Array#sum and Enumerable#sum are implemented.  [Feature #12217]
+
+  Ruby itself has no compatibility problem because Ruby didn't have sum method
+  for arrays before Ruby 2.4.
+  However many third party gems, activesupport, facets, simple_stats, etc,
+  defines sum method.  These implementations are mostly compatible but
+  there are subtle differences.
+  Ruby's sum method should be mostly compatible but it is impossible to
+  be perfectly compatible with all of them.
+
+* Fixnum and Bignum are unified into Integer  [Feature #12005]
+
+  Fixnum class and Bignum class is removed.
+  Integer class is changed from abstract class to concrete class.
+  For example, 0 is an instance of Integer: 0.class returns Integer.
+  The constants Fixnum and Bignum is bound to Integer.
+  So obj.kind_of?(Fixnum) works as obj.kind_of?(Integer).
+  At C-level, Fixnum object and Bignum object should be distinguished by
+  FIXNUM_P(obj) and RB_TYPE_P(obj, T_BIGNUM).
+  RUBY_INTEGER_UNIFICATION can be used to detect this feature at C-level.
+  0.class == Integer can be used to detect this feature at Ruby-level.
+  The C-level constants, rb_cFixnum and rb_cBignum, are removed.
+  They can cause compilation failure.
+
+* String/Symbol#upcase/downcase/swapcase/capitalize(!) now work for all of
+  Unicode, not only for ASCII. [Feature #10085]
+
+  No change is needed if the data is in ASCII anyway or if the limitation
+  to ASCII was only tolerated while waiting for a more extensive implementation.
+  A change (using the :ascii option) is needed in cases where Unicode data
+  is processed, but the operation has to be limited to ASCII only.
+  A good example of this are internationalized domain names.
+
+* TRUE / FALSE / NIL
+
+  These constants are now obsoleted. [Feature #12574]
+  Use true / false / nil resp. instead.
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* DateTime
+
+  * DateTime#to_time now preserves timezone.  [Bug #12189]
+
+* Psych
+
+  * Update to Psych 2.2.2
+
+* RDoc
+
+  * Update to RDoc 5.0.0
+
+* RubyGems
+
+  * Update to RubyGems 2.6.8
+
+* shellwords
+
+  * Shellwords.shellwords (shellsplit) treats the backslash as escape
+    character only when followed by one of the following characters:
+    $ ` " \ <newline> [Bug #10055]
+
+* Time
+
+  * Time#to_time now preserves timezone.  [Bug #12271]
+
+* thread
+
+  * the extension library is removed.  Till 2.0 it was a pure ruby script
+    "thread.rb", which has precedence over "thread.so", and has been provided
+    in $LOADED_FEATURES since 2.1.
+
+* Tk
+
+  * Tk is removed from stdlib.  [Feature #8539]
+
+    https://github.com/ruby/tk is the new upstream.
+
+* XMLRPC
+
+  * XMLRPC is removed from stdlib, and bundled as gem. [Feature #12160][ruby-core:74239]
+
+    https://github.com/ruby/xmlrpc is the new upstream.
+
+* Zlib
+
+  * Zlib.gzip and Zlib.gunzip [Feature #13020]
+
+=== C API updates
+
+* ruby_show_version() will no longer exits the process, if
+  RUBY_SHOW_COPYRIGHT_TO_DIE is set to 0.  This will be the default in
+  the future.
+
+* rb_gc_adjust_memory_usage() [Feature #12690]
+
+=== Supported platform changes
+
+* FreeBSD < 4 is no longer supported
+
+=== Implementation improvements
+
+* In some condition, `[x, y].max` and `[x, y].min` are optimized
+  so that a temporal array is not created.  The concrete condition is
+  an implementation detail: currently, the array literal must have no
+  splat, must have at least one expression but literal, the length must
+  be <= 0x100, and Array#max and min must not be redefined.  It will work
+  in most casual and real-life use case where it is written with intent
+  to `Math.max(x, y)`.
+
+* Thread deadlock detection now shows their backtrace and dependency. [Feature #8214]
+
+* st_table (st.c) internal data structure is improved. [Feature #12142]
+
+* Rational is extensively optimized. [Feature #12484]
+
+=== Miscellaneous changes
+
+* ChangeLog is removed from the repository.
+
+  It is generated from commit messages in Subversion by `make dist`.
+  Also note that now people should follow Git style commit message.
+  The template is written at {Short (50 chars or less) summary of
+  changes}[https://git-scm.com/book/ch5-2.html].  [Feature #12283]
diff --git a/doc/NEWS/NEWS-2.5.0 b/doc/NEWS/NEWS-2.5.0
new file mode 100644
index 0000000000..af7f3ada01
--- /dev/null
+++ b/doc/NEWS/NEWS-2.5.0
@@ -0,0 +1,565 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.5.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or
+reference information is supplied with.  For a full list of changes
+with all sufficient information, see the ChangeLog file or Redmine
+(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
+
+== Changes since the 2.4.0 release
+
+=== Language changes
+
+* Top-level constant look-up is removed.  [Feature #11547]
+
+* rescue/else/ensure are allowed inside do/end blocks.  [Feature #12906]
+
+* refinements take place in string interpolations.  [Feature #13812]
+
+=== Core classes updates (outstanding ones only)
+
+* Array
+
+  * New methods:
+
+    * Array#append  [Feature #12746]
+    * Array#prepend  [Feature #12746]
+
+* Data
+
+  * Is deprecated. It was a base class for C extensions, and it's not
+    necessary to expose in Ruby level. [Feature #3072]
+
+* Exception
+
+  * New methods:
+
+    * Exception#full_message to retrieve a String expression of an exception,
+      formatted in the same way in which Ruby prints out an uncaught
+      exception.  [Feature #14141] [experimental]
+
+* Dir
+
+  * Dir.glob provides new optional keyword argument, +:base+ .  [Feature #13056]
+  * Dir.chdir (without block arg), Dir.open, Dir.new, Dir.mkdir, Dir.rmdir,
+    Dir.empty? releases GVL
+
+  * New methods:
+
+    * Dir.children  [Feature #11302]
+    * Dir.each_child  [Feature #11302]
+
+* Enumerable
+
+  * Enumerable#any?, Enumerable#all?, Enumerable#none? and Enumerable#one?
+    accept a pattern argument. [Feature #11286]
+
+* File
+
+  * File.open accepts +:newline+ option to imply text mode. [Bug #13350]
+  * File#path raises an IOError for files opened with
+    File::Constants::TMPFILE option. [Feature #13568]
+  * File.stat, File.exist? and other <code>rb_stat()</code>-using methods
+    release GVL. [Bug #13941]
+  * File.rename releases GVL. [Feature #13951]
+  * File::Stat#atime, File::Stat#mtime and File::Stat#ctime support fractional
+    second timestamps on Windows 8 and later.  [Feature #13726]
+  * File::Stat#ino and File.identical? support ReFS 128bit ino on Windows 8.1
+    and later.  [Feature #13731]
+  * File.readable?, File.readable_real?, File.writable?, File.writable_real?,
+    File.executable?, File.executable_real?, File.mkfifo, File.readlink,
+    File.truncate, File#truncate, File.chmod, File.lchmod, File.chown,
+    File.lchown, File.unlink, File.utime, File.lstat release GVL
+
+  * New method:
+
+    * File.lutime  [Feature #4052]
+
+* Hash
+
+  * New methods:
+
+    * Hash#transform_keys  [Feature #13583]
+    * Hash#transform_keys!  [Feature #13583]
+    * Hash#slice  [Feature #8499]
+
+* IO
+
+  * IO.copy_stream tries copy offload with copy_file_range(2) [Feature #13867]
+
+  * New methods:
+
+    * IO#pread  [Feature #4532]
+    * IO#pwrite  [Feature #4532]
+    * IO#write accepts multiple arguments  [Feature #9323]
+
+* IOError
+
+  * IO#close might raise an error with message "stream closed",
+    but it is refined to "stream closed in another thread". The new message
+    is more clear for user. [Bug #13405]
+
+* Integer
+
+  * Integer#round, Integer#floor, Integer#ceil and Integer#truncate always
+    return an Integer. [Bug #13420]
+  * Integer#pow accepts modulo argument for calculating modular
+    exponentiation.  [Feature #12508] [Feature #11003]
+
+  * New methods:
+
+    * Integer#allbits?, Integer#anybits?, Integer#nobits? [Feature #12753]
+    * Integer.sqrt  [Feature #13219]
+
+* Kernel
+
+  * Kernel#yield_self   [Feature #6721]
+  * Kernel#pp  [Feature #14123]
+  * Kernel#warn(..., uplevel:n)  [Feature #12882]
+
+* Method
+
+  * New methods:
+
+    * Method#=== that invokes Method#call, as same as Proc#=== [Feature #14142]
+
+* Module
+
+  * Module#attr, Module#attr_accessor, Module#attr_reader and Module#attr_writer
+    become public. [Feature #14132]
+  * Module#define_method, Module#alias_method, Module#undef_method and
+    Module#remove_method become public. [Feature #14133]
+
+* Numeric
+
+  * Numeric#step no longer hides errors from coerce method when
+    given a step value which cannot be compared with #> to 0. [Feature #7688]
+  * Numerical comparison operators (<,<=,>=,>) no longer hide exceptions
+    from #coerce method internally. Return nil in #coerce if the coercion is
+    impossible.  [Feature #7688]
+
+* Process
+
+  * Precision of Process.times is improved if getrusage(2) exists. [Feature #11952]
+
+  * New method:
+
+    * Process.last_status as an alias of $? [Feature #14043]
+
+* Range
+  * Range#initialize no longer hides exceptions when comparing begin and
+    end with #<=> and raise a "bad value for range" ArgumentError
+    but instead lets the exception from the #<=> call go through. [Feature #7688]
+
+* Regexp
+
+  * Update to Onigmo 6.1.3-669ac9997619954c298da971fcfacccf36909d05.
+
+    * Support absence operator https://github.com/k-takata/Onigmo/issues/82
+
+  * Support new 5 emoji-related Unicode character properties
+
+* RubyVM::InstructionSequence
+
+  * New method:
+
+    * RubyVM::InstructionSequence#each_child
+    * RubyVM::InstructionSequence#trace_points
+
+* String
+
+  * <code>String#-@</code> deduplicates unfrozen strings.  Already-frozen
+    strings remain unchanged for compatibility.  [Feature #13077]
+  * <code>-"literal"</code> (<code>String#-@</code>) optimized to return the same object
+    (same as <code>"literal".freeze</code> in Ruby 2.1+) [Feature #13295]
+  * String#casecmp and String#casecmp? return nil for non-string arguments
+    instead of raising a TypeError. [Bug #13312]
+  * String#start_with? accepts a regexp [Feature #13712]
+
+  * New methods:
+
+    * String#delete_prefix, String#delete_prefix! [Feature #12694]
+    * String#delete_suffix, String#delete_suffix! [Feature #13665]
+    * String#each_grapheme_cluster and String#grapheme_clusters to
+      enumerate grapheme clusters [Feature #13780]
+    * String#undump to unescape String#dump'ed string [Feature #12275]
+
+* Struct
+
+  * Struct.new takes `keyword_init: true` option to initialize members
+    with keyword arguments. [Feature #11925]
+
+* Regexp/String: Update Unicode version from 9.0.0 to 10.0.0 [Feature #13685]
+
+* Thread
+
+  * Description set by Thread#name= is now visible on Windows 10.
+
+  * New method:
+    * Thread#fetch  [Feature #13009]
+
+  * The default of Thread.report_on_exception is now true,
+    showing unhandled exceptions terminating threads on $stderr. [Feature #14143]
+
+* Time
+
+  * Time.at receives 3rd argument which specifies the unit of 2nd argument. [Feature #13919]
+
+* KeyError
+
+  * New methods:
+
+    * KeyError#receiver [Feature #12063]
+    * KeyError#key      [Feature #12063]
+
+* FrozenError
+
+  * New exception class. [Feature #13224]
+
+=== Stdlib updates (outstanding ones only)
+
+* BigDecimal
+
+  * Update to BigDecimal 1.3.4
+
+  * The following features are added:
+
+    * BigDecimal::VERSION
+
+  * The following features have been deprecated,
+    and are planned to be removed in the version 1.4.0:
+
+    * BigDecimal.new
+
+    * BigDecimal.ver
+
+  * BigDecimal#clone and #dup now do not make a new instance,
+    but returns the receiver itself.
+
+* Coverage
+
+  * Support branch coverage and method coverage measurement. [Feature #13901]
+    Branch coverage tells you which branches are executed, and which not.
+    Method coverage tells you which methods are invoked, and which not.
+    By running a test suite with this new feature, you can know which branches
+    and methods are executed by a test, and evaluate total coverage of a test
+    suite more strictly.
+
+    You can specify the measuring target by an option to `Coverage.start`:
+
+        Coverage.start(lines: true, branches: true, methods: true)
+
+    After some Ruby files are loaded, you can use `Coverage.result` to get
+    the coverage result:
+
+        Coverage.result
+        #=> { "/path/to/file.rb"=>
+        #     { :lines => [1, 2, 0, nil, ...],
+        #       :branches =>
+        #         { [:if, 0, 2, 1, 6, 4] =>
+        #             { [:then, 1, 3, 2, 3, 8] => 0,
+        #               [:else, 2, 5, 2, 5, 8] => 2
+        #             }
+        #         },
+        #       :methods => {
+        #          [Object, :foo, 1, 0, 7, 3] => 2
+        #       }
+        #     }
+        #   }
+
+    The result type of line coverage is not changed; it is just an array that
+    contains numbers, which means the count that each line was executed,
+    or `nil`s, which means that the line is not relevant.
+
+    The result type of branch coverage is:
+
+        { (jump base) => { (jump target) => (counter) } }
+
+    where jump base and targets have the format
+
+        [type, unique-id, start lineno, start column, end lineno, end column]
+
+    For example, `[:if, 0, 2, 1, 6, 4]` reads an `if` statement that ranges from
+    line 2 and column 1, to line 6 and column 4.  `[:then, 1, 3, 2, 3, 8]` reads
+    a `then` clause that ranges from line 3 and column 2, to line 3 and column 8.
+    Note that lineno starts from 1, and that columnno starts from 0.  So, the
+    above example shows a branch from the `if` to the `then` was never executed,
+    and a branch from the `if` to the `else` was executed twice.
+
+    The result type of method coverage is:
+
+        { (method key) => (counter) }
+
+    where method key has the format
+
+        [class, method-name, start lineno, start column, end lineno, end column]
+
+    For example, `[Object, :foo, 1, 0, 7, 3]` reads `Object#foo` that ranges from
+    line 1 and column 0, to line 7 and column 3.  The above example shows this
+    `Object#foo` was invoked twice.
+
+    Note: To keep compatibility, passing no option to `Coverage.start` will measure
+    only line coverage, and `Coverage.result` will return the old format:
+
+        Coverage.result
+        #=> { "/path/to/file.rb"=> [1, 2, 0, nil, ...] }
+
+* DRb
+
+  * ACL::ACLEntry.new no longer suppresses IPAddr::InvalidPrefixError.
+
+* ERB
+
+  * Add ERB#result_with_hash to render a template with local variables passed
+    with a Hash object. [Feature #8631]
+
+  * Default template file encoding is changed from ASCII-8BIT to UTF-8 in erb
+    command. [Bug #14095]
+
+  * Carriage returns are changed to be trimmed properly if trim_mode is specified
+    and used. Duplicated newlines will be removed on Windows. [Bug #5339] [Bug #11464]
+
+* IPAddr
+
+  * IPAddr no longer accepts invalid address mask. [Bug #13399]
+  * IPAddr#ipv4_compat and IPAddr#ipv4_compat? are marked for deprecation. [Bug #13769]
+
+  * New methods:
+
+    * IPAddr#prefix
+    * IPAddr#loopback?
+    * IPAddr#private? [Feature #11666]
+    * IPAddr#link_local? [Feature #10912]
+
+* IRB
+
+  * Print backtrace and error message in reverse order [Feature #8661] [experimental]
+  * `binding.irb` automatically requires irb and runs [Bug #13099] [experimental]
+  * `binding.irb` on its start shows source around the line where it was called [Feature #14124]
+
+* Matrix
+
+  * New methods:
+
+    * Matrix.combine and Matrix#combine [Feature #10903]
+    * Matrix#hadamard_product and Matrix#entrywise_product
+
+* Net::HTTP
+
+  * Net::HTTP.new supports no_proxy parameter [Feature #11195]
+  * Net::HTTP#min_version and Net::HTTP#max_version [Feature #9450]
+  * Add more HTTP status classes
+  * Net::HTTP::STATUS_CODES is added as HTTP Status Code Repository [Misc #12935]
+  * Net::HTTP#proxy_user and Net::HTTP#proxy_pass reflect http_proxy environment
+    variable if the system's environment variable is multiuser safe. [Bug #12921]
+
+* open-uri
+  * URI.open method defined as an alias to open-uri's Kernel.open.
+    open-uri's Kernel.open will be deprecated in future.
+
+* OpenSSL
+
+  * Updated Ruby/OpenSSL from version 2.0 to 2.1. Changes are noted in
+    "Version 2.1.0" section in ext/openssl/History.md.
+
+* Pathname
+
+  * New method:
+
+    * Pathname#glob [Feature #7360]
+
+* Psych
+
+  * Update to Psych 3.0.2.
+
+    * Convert fallback option to a keyword argument
+      https://github.com/ruby/psych/pull/342
+    * Add :symbolize_names option to Psych.load, Psych.safe_load like JSON.parse
+      https://github.com/ruby/psych/pull/333, https://github.com/ruby/psych/pull/337
+    * Add Psych::Handler#event_location
+      https://github.com/ruby/psych/pull/326
+    * Make frozen string literal = true
+      https://github.com/ruby/psych/pull/320
+    * Preserve time zone offset when deserializing times
+      https://github.com/ruby/psych/pull/316
+    * Remove deprecated method aliases for syck gem
+      https://github.com/ruby/psych/pull/312
+
+* RbConfig
+
+  * RbConfig::LIMITS is added to provide the limits of C types.
+    This is available when rbconfig/sizeof is loaded.
+
+* Ripper
+
+  * Ripper::EXPR_BEG and so on for Ripper#state.
+
+  * New method:
+
+    * Ripper#state to tell the state of scanner. [Feature #13686]
+
+* RDoc
+
+  * Update to RDoc 6.0.1.
+
+    * Replace IRB based lexer with Ripper.
+      * https://github.com/ruby/rdoc/pull/512
+      * This much improves the speed of generating documents.
+      * It also facilitates supporting new syntax in the future.
+    * Support many new syntaxes of Ruby from the past few years.
+    * Use "frozen_string_literal: true".
+      Performance survey: https://gist.github.com/aycabta/abdfaa75ea8a6877eeb734e942e73800
+    * Support did_you_mean.
+
+* Rubygems
+
+  * Update to Rubygems 2.7.3.
+    * http://blog.rubygems.org/2017/11/28/2.7.3-released.html
+    * http://blog.rubygems.org/2017/11/08/2.7.2-released.html
+    * http://blog.rubygems.org/2017/11/03/2.7.1-released.html
+    * http://blog.rubygems.org/2017/11/01/2.7.0-released.html
+    * http://blog.rubygems.org/2017/10/09/2.6.14-released.html
+    * http://blog.rubygems.org/2017/08/27/2.6.13-released.html
+
+* SecureRandom
+
+  * New method:
+
+    * SecureRandom.alphanumeric
+
+* Set
+
+  * New methods:
+
+    * Set#to_s as alias to #inspect [Feature #13676]
+    * Set#=== as alias to #include? [Feature #13801]
+    * Set#reset [Feature #6589]
+
+* StringIO
+
+  * StringIO#write accepts multiple arguments
+
+* StringScanner
+
+  * New methods:
+
+    * StringScanner#size, StringScanner#captures, StringScanner#values_at  [Feature #836]
+
+* URI
+
+  * Relative path operations no longer collapse consecutive slashes to a single slash. [Bug #8352]
+
+* WEBrick
+
+  * Add Server Name Indication (SNI) support [Feature #13729]
+  * support Proc objects as body responses [Feature #855]
+  * released as a RubyGem [Feature #13173]
+  * avoid unintended behavior from Kernel#open [Misc #14216]
+
+* Zlib
+
+  * Zlib::GzipWriter#write accepts multiple arguments
+
+=== Compatibility issues (excluding feature bug fixes)
+
+* BasicSocket
+
+  * BasicSocket#read_nonblock and BasicSocket#write_nonblock no
+    longer set the O_NONBLOCK file description flag as side effect
+    (on Linux only) [Feature #13362]
+
+* Random
+
+  * Random.raw_seed renamed to become Random.urandom.  It is now
+    applicable to non-seeding purposes due to [Bug #9569].
+
+* Socket
+
+  * Socket::Ifaddr#vhid is added [Feature #13803]
+
+* ConditionVariable, Queue and SizedQueue reimplemented for speed.
+  They no longer subclass Struct. [Feature #13552]
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* Gemification
+
+  * Promote following standard libraries to default gems.
+    * cmath
+    * csv
+    * date
+    * dbm
+    * etc
+    * fcntl
+    * fiddle
+    * fileutils
+    * gdbm
+    * ipaddr
+    * scanf
+    * sdbm
+    * stringio
+    * strscan
+    * webrick
+    * zlib
+
+* Logger
+
+  * Logger.new("| command") had been working to open a command
+    unintentionally. It was prohibited, and now Logger#initialize
+    treats a String argument only as a filename, as its specification. [Bug #14212]
+
+* Net::HTTP
+
+  * Net::HTTP#start now passes :ENV to p_addr by default. [Bug #13351]
+    To avoid this, pass nil explicitly.
+
+* mathn.rb
+
+  * Removed from stdlib. [Feature #10169]
+
+* Rubygems
+
+  * Removed "ubygems.rb" file from stdlib. It's needless since Ruby 1.9.
+
+=== Supported platform changes
+
+* Drop support of NaCl platform
+
+  * https://bugs.chromium.org/p/chromium/issues/detail?id=239656#c160
+
+=== Implementation improvements
+
+* (This might not be a "user visible feature change" but) Hash class's
+  hash function is now SipHash13. [Feature #13017]
+
+* SecureRandom now prefers OS-provided sources than OpenSSL. [Bug #9569]
+
+* Mutex rewritten to be smaller and faster [Feature #13517]
+
+* Performance of block passing using block parameters is improved by
+  lazy Proc allocation [Feature #14045]
+
+* Dynamic instrumentation for TracePoint hooks instead of using "trace"
+  instruction to avoid overhead [Feature #14104]
+
+* ERB now generates code from a template twice as fast as Ruby 2.4
+
+=== Miscellaneous changes
+
+* Print backtrace and error message in reverse order if $stderr is unchanged
+  and a tty. [Feature #8661] [experimental]
+
+* Print error message in bold/underlined text if $stderr is unchanged and a
+  tty. [Feature #14140] [experimental]
+
+* configure option --with-ext now mandates its arguments.  So for
+  instance if you run ./configure --with-ext=openssl,+ then the
+  openssl library is guaranteed compiled, otherwise the build fails
+  abnormally.
+
+  Note however to always add the ",+" at the end of the argument.
+  Otherwise nothing but openssl are built.  [Feature #13302]
diff --git a/doc/NEWS/NEWS-2.6.0 b/doc/NEWS/NEWS-2.6.0
new file mode 100644
index 0000000000..6e70696de2
--- /dev/null
+++ b/doc/NEWS/NEWS-2.6.0
@@ -0,0 +1,662 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.6.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or reference
+information is supplied with.  For a full list of changes with all
+sufficient information, see the ChangeLog file or Redmine
+(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
+
+== Changes since the 2.5.0 release
+
+=== Language changes
+
+* <code>$SAFE</code> now is a process global state and can be set to 0 again. [Feature #14250]
+
+* Refinements take place at block passing.  [Feature #14223]
+
+* Refinements take place at Kernel#public_send.  [Feature #15326]
+
+* Refinements take place at Kernel#respond_to?.  [Feature #15327]
+
+* +else+ without +rescue+ now causes a syntax error.  [EXPERIMENTAL] [Feature #14606]
+
+* Constant names may start with a non-ASCII capital letter. [Feature #13770]
+
+* Endless ranges are introduced.  You can use a Range that has no end,
+  like <code>(0..)</code> (or similarly <code>(0...)</code>).  [Feature #12912]
+
+  The following shows typical use cases:
+
+    ary[1..]                              # identical to ary[1..-1]
+    (1...).each {|index| block }          # infinite loop from index 1
+    ary.zip(1..) {|elem, index| block }   # ary.each.with_index(1) { }
+
+* Non-Symbol keys in a keyword arguments hash cause an exception.
+
+* The "shadowing outer local variable" warning is removed.  [Feature #12490]
+
+  You can now write the following without warning:
+
+    user = users.find {|user| cond(user) }
+
+* Print +cause+ of the exception if the exception is not caught and printed
+  its backtraces and error message. [Feature #8257]
+
+* The flip-flop syntax is deprecated. [Feature #5400]
+
+=== Core classes updates (outstanding ones only)
+
+[Array]
+
+  [New methods]
+
+    * Added Array#union and Array#difference instance methods.  [Feature #14097]
+
+  [Modified method]
+
+    * Array#to_h now accepts a block that maps elements to new key/value pairs.  [Feature #15143]
+
+  [Aliased methods]
+
+    * Array#filter is a new alias for Array#select. [Feature #13784]
+    * Array#filter! is a new alias for Array#select!. [Feature #13784]
+
+[Binding]
+
+  [New method]
+
+    * Added Binding#source_location.  [Feature #14230]
+
+      This method returns the source location of the binding, a 2-element
+      array of <code>__FILE__</code> and <code>__LINE__</code>.
+      Traditionally, the same information could be retrieved by
+      <code>eval("[__FILE__, __LINE__]", binding)</code>, but we are
+      planning to change this behavior so that Kernel#eval ignores
+      binding's source location [Bug #4352].  So, users should use this
+      newly-introduced method instead of Kernel#eval.
+
+[Dir]
+
+  [New methods]
+
+    * Added Dir#each_child and Dir#children instance methods. [Feature #13969]
+
+[Enumerable]
+
+  [New method]
+
+    * Enumerable#chain returns an enumerator object that iterates over the
+      elements of the receiver and then those of each argument
+      in sequence.  [Feature #15144]
+
+  [Modified method]
+
+    * Enumerable#to_h now accepts a block that maps elements to new key/value pairs.  [Feature #15143]
+
+  [Aliased method]
+
+    * Enumerable#filter is a new alias for Enumerable#select. [Feature #13784]
+
+[Enumerator::ArithmeticSequence]
+
+  * This is a new class to represent a generator of an arithmetic sequence,
+    that is a number sequence defined by a common difference. It can be used
+    for representing what is similar to Python's slice. You can get an
+    instance of this class from Numeric#step and Range#step.
+
+[Enumerator::Chain]
+
+  * This is a new class to represent a chain of enumerables that works as a
+    single enumerator, generated by such methods as Enumerable#chain and
+    Enumerator#+.
+
+[Enumerator::Lazy]
+
+  [Aliased method]
+
+    * Enumerator::Lazy#filter is a new alias for
+      Enumerator::Lazy#select.  [Feature #13784]
+
+[Enumerator]
+
+  [New methods]
+
+    * Enumerator#+ returns an enumerator object that iterates over the
+      elements of the receiver and then those of the other operand.  [Feature #15144]
+
+[ENV]
+
+  [Modified method]
+
+    * ENV.to_h now accepts a block that maps names and values to new keys and values.  [Feature #15143]
+
+[Exception]
+
+  [New options]
+
+    * Exception#full_message takes +:highlight+ and +:order+
+      options. [Bug #14324]
+
+[Hash]
+
+  [Modified methods]
+
+    * Hash#merge, Hash#merge!, and Hash#update now accept multiple
+      arguments.  [Feature #15111]
+
+    * Hash#to_h now accepts a block that maps keys and values to new keys and values.  [Feature #15143]
+
+  [Aliased methods]
+
+    * Hash#filter is a new alias for Hash#select.  [Feature #13784]
+
+    * Hash#filter! is a new alias for Hash#select!. [Feature #13784]
+
+[IO]
+
+  [New option]
+
+    * Added new mode character <code>'x'</code> to open files for exclusive
+      access. [Feature #11258]
+
+[Kernel]
+
+  [Aliased method]
+
+    * Kernel#then is a new alias for Kernel#yield_self. [Feature #14594]
+
+  [New options]
+
+    * Kernel#Complex, Kernel#Float, Kernel#Integer, and
+      Kernel#Rational take an +:exception+ option to specify the way of
+      error handling.  [Feature #12732]
+
+    * Kernel#system takes an +:exception+ option to raise an exception
+      on failure.  [Feature #14386]
+
+  [Incompatible changes]
+
+    * Kernel#system and Kernel#exec do not close non-standard file descriptors
+      (the default of the +:close_others+ option is changed to +false+,
+      but we still set the +FD_CLOEXEC+ flag on descriptors we
+      create).  [Misc #14907]
+
+[KeyError]
+
+  [New options]
+
+    * KeyError.new accepts +:receiver+ and +:key+ options to set receiver and
+      key in Ruby code.  [Feature #14313]
+
+[Method]
+
+  [New methods]
+
+    * Added Method#<< and Method#>> for Proc composition.  [Feature #6284]
+
+[Module]
+
+  [Modified methods]
+
+    * Module#method_defined?, Module#private_method_defined?, and
+      Module#protected_method_defined? now accept the second
+      parameter as optional. If it is +true+ (the default value), it checks
+      ancestor modules/classes, or checks only the class itself. [Feature #14944]
+
+[NameError]
+
+  [New option]
+
+    * NameError.new accepts a +:receiver+ option to set receiver in Ruby
+      code.  [Feature #14313]
+
+[NilClass]
+
+  [New method]
+
+    * NilClass#=~ is added for compatibility.  [Feature #15231]
+
+[NoMethodError]
+
+  [New option]
+
+    * NoMethodError.new accepts a +:receiver+ option to set receiver in Ruby
+      code.  [Feature #14313]
+
+[Numeric]
+
+  [Incompatible changes]
+
+    * Numeric#step now returns an instance of the Enumerator::ArithmeticSequence
+      class rather than one of the Enumerator class.
+
+[OpenStruct]
+
+  [Modified method]
+
+    * OpenStruct#to_h now accepts a block that maps keys and values to new keys and values.  [Feature #15143]
+
+[Proc]
+
+  [New methods]
+
+    * Added Proc#<< and Proc#>> for Proc composition.  [Feature #6284]
+
+  [Incompatible changes]
+
+    * Proc#call doesn't change <code>$SAFE</code> any more.  [Feature #14250]
+
+[Random]
+
+  [New method]
+
+    * Added Random.bytes.  [Feature #4938]
+
+[Range]
+
+  [New method]
+
+    * Added Range#% instance method.  [Feature #14697]
+
+  [Incompatible changes]
+
+    * Range#=== now uses the +#cover?+ instead of the +#include?+ method. [Feature #14575]
+    * Range#cover? now accepts a Range object. [Feature #14473]
+    * Range#step now returns an instance of the Enumerator::ArithmeticSequence
+      class rather than one of the Enumerator class.
+
+[Regexp/String]
+
+    * Update Unicode version from 10.0.0 to 11.0.0. [Feature #14802]
+
+      This includes a rewrite of the grapheme cluster (/\X/) algorithm
+      and special-casing for Georgian MTAVRULI on String#downcase.
+
+    * Update Emoji version from 5.0 to 11.0.0 [Feature #14802]
+
+[RubyVM::AbstractSyntaxTree]
+
+  [New methods]
+
+    * RubyVM::AbstractSyntaxTree.parse parses a given string and returns AST
+      nodes. [experimental]
+
+    * RubyVM::AbstractSyntaxTree.parse_file parses a given file and returns AST
+      nodes.  [experimental]
+
+    * RubyVM::AbstractSyntaxTree.of returns AST nodes of the given proc or
+      method.  [experimental]
+
+[RubyVM]
+
+  [New method]
+
+    * RubyVM.resolve_feature_path identifies the file that will be loaded by
+      "require(feature)". [experimental] [Feature #15230]
+
+[String]
+
+  * String#crypt is now deprecated. [Feature #14915]
+
+  [New features]
+
+    * String#split yields each substring to the block if given. [Feature #4780]
+
+[Struct]
+
+  [Modified method]
+
+    * Struct#to_h now accepts a block that maps keys and values to new keys and values.  [Feature #15143]
+
+  [Aliased method]
+
+    * Struct#filter is a new alias for Struct#select. [Feature #13784]
+
+[Time]
+
+  [New features]
+
+    * Time.new and Time#getlocal accept a timezone object as well as
+      a UTC offset string. Time#+, Time#-, and Time#succ also preserve
+      the timezone.  [Feature #14850]
+
+[TracePoint]
+
+  [New features]
+
+    * "script_compiled" event is supported. [Feature #15287]
+
+  [New methods]
+
+    * TracePoint#parameters [Feature #14694]
+
+    * TracePoint#instruction_sequence [Feature #15287]
+
+    * TracePoint#eval_script [Feature #15287]
+
+  [Modified method]
+
+    * TracePoint#enable accepts new keywords "target:" and
+      "target_line:".  [Feature #15289]
+
+=== Stdlib updates (outstanding ones only)
+
+[BigDecimal]
+
+  Update to version 1.4.0.  This version includes several compatibility
+  issues, see Compatibility issues section below for details.
+
+  [Modified method]
+
+    * BigDecimal() accepts the new keyword "exception:" similar to Float().
+
+  [Note for the differences among recent versions]
+
+    You should want to know the differences among recent versions of bigdecimal.
+    Please select the suitable version of bigdecimal according to the following
+    information.
+
+    * 1.3.5 has BigDecimal.new without "exception:" keyword.  You can see the
+      deprecation warning of BigDecimal.new when you specify "-w" option.
+      BigDecimal(), BigDecimal.new, and Object#to_d methods are the same.
+
+    * 1.4.0 has BigDecimal.new with "exception:" keyword.  You always see the
+      deprecation warning of BigDecimal.new.  Object#to_d method is different
+      from BigDecimal() and BigDecimal.new.
+
+    * 2.0.0 will be released soon after releasing Ruby 2.6.0.  This version
+      will not have the BigDecimal.new method.
+
+[Bundler]
+
+  * Add Bundler to Standard Library. [Feature #12733]
+
+  * Use 1.17.2, the latest stable version.
+
+[Coverage]
+
+  A oneshot_lines mode is added.  [Feature #15022]
+
+  This mode checks "whether each line was executed at least once or not",
+  instead of "how many times each line was executed".
+  A hook for each line is fired at most once, and after it is fired
+  the hook flag is removed, i.e., it runs with zero overhead.
+
+  [New options]
+
+    * Add +:oneshot_lines+ keyword argument to Coverage.start.
+
+    * Add +:stop+ and +:clear+ keyword arguments to Coverage.result.
+      If +clear+ is true, it clears the counters to zero.
+      If +stop+ is true, it disables coverage measurement.
+
+  [New methods]
+
+    * Coverage.line_stub, which is a simple helper function that
+      creates the "stub" of line coverage from a given source code.
+
+[CSV]
+
+  * Upgrade to 3.0.2. This includes performance improvements especially
+    for writing. Writing is about 2 times faster.
+    See https://github.com/ruby/csv/blob/master/NEWS.md.
+
+[ERB]
+
+  [New options]
+
+    * Add +:trim_mode+ and +:eoutvar+ keyword arguments to ERB.new.
+      Now non-keyword arguments other than the first one are softly deprecated
+      and will be removed when Ruby 2.5 becomes EOL. [Feature #14256]
+
+    * erb command's <tt>-S</tt> option is deprecated, and will be removed
+      in the next version.
+
+[FileUtils]
+
+  [New methods]
+
+    * FileUtils#cp_lr.  [Feature #4189]
+
+[Matrix]
+
+  [New methods]
+
+    * Matrix#antisymmetric?, Matrix#skew_symmetric?
+
+    * Matrix#map!, Matrix#collect! [Feature #14151]
+
+    * Matrix#[]=
+
+    * Vector#map!, Vector#collect!
+
+    * Vector#[]=
+
+[Net]
+
+  [New options]
+
+    * Add +:write_timeout+ keyword argument to Net::HTTP.new. [Feature #13396]
+
+  [New methods]
+
+    * Add Net::HTTP#write_timeout and Net::HTTP#write_timeout=.  [Feature #13396]
+
+  [New constant]
+
+    * Add Net::HTTPClientException to deprecate Net::HTTPServerException,
+      whose name is misleading.  [Bug #14688]
+
+[NKF]
+
+  * Upgrade to nkf v2.1.5
+
+[Psych]
+
+  * Upgrade to Psych 3.1.0
+
+[RDoc]
+
+  * Become about 2 times faster.
+
+  * Use SOURCE_DATE_EPOCH to generate files.
+
+  * Fix method line number that slipped off.
+
+  * Enable <code>--width</code>, <code>--exclude</code>,
+    and <code>--line-numbers</code> that were ignored.
+
+  * Add support for blockquote by ">>>" in default markup notation.
+
+  * Add support for "Raises" lines in TomDoc notation.
+
+  * Fix syntax error output.
+
+  * Fix many parsing bugs.
+
+[REXML]
+
+  * Upgrade to REXML 3.1.9.
+    See https://github.com/ruby/rexml/blob/master/NEWS.md.
+
+  [Improved some XPath implementations]
+
+    * <code>concat()</code> function: Stringify all arguments before concatenating.
+
+    * <code>string()</code> function: Support context node.
+
+    * <code>string()</code> function: Support processing instruction node.
+
+    * Support <code>"*:#{ELEMENT_NAME}"</code> syntax in XPath 2.0.
+
+  [Fixed some XPath implementations]
+
+    * <code>"//#{ELEMENT_NAME}[#{POSITION}]"</code> case
+
+    * <code>string()</code> function: Fix <code>function(document)</code>
+      returns nodes that are out of root elements.
+
+    * <code>"/ #{ELEMENT_NAME} "</code> case
+
+    * <code>"/ #{ELEMENT_NAME} [ #{PREDICATE} ]"</code> case
+
+    * <code>"/ #{AXIS}::#{ELEMENT_NAME}"</code> case
+
+    * <code>"#{N}-#{M}"</code> case: One or more white spaces were required
+      before <code>"-"</code>
+
+    * <code>"/child::node()"</code> case
+
+    * <code>"#{FUNCTION}()/#{PATH}"</code> case
+
+    * <code>"@#{ATTRIBUTE}/parent::"</code> case
+
+    * <code>"name(#{NODE_SET})"</code> case
+
+[RSS]
+
+  [New options]
+
+    * RSS::Parser.parse now accepts options as Hash. +:validate+ ,
+      +:ignore_unknown_element+ , +:parser_class+ options are available.
+
+[RubyGems]
+
+  * Upgrade to RubyGems 3.0.1
+
+  * https://blog.rubygems.org/2018/12/19/3.0.0-released.html
+
+  * https://blog.rubygems.org/2018/12/23/3.0.1-released.html
+
+[Set]
+
+  [Aliased method]
+
+    * Set#filter! is a new alias for Set#select!.  [Feature #13784]
+
+[URI]
+
+  [New constant]
+
+    * Add URI::File to handle the file URI scheme.  [Feature #14035]
+
+=== Compatibility issues (excluding feature bug fixes)
+
+[Dir]
+
+  * Dir.glob with <code>'\0'</code>-separated pattern list will be deprecated,
+    and is now warned.  [Feature #14643]
+
+[File]
+
+  * File.read, File.binread, File.write, File.binwrite, File.foreach, and
+    File.readlines do not invoke external commands even if the path starts
+    with the pipe character <code>'|'</code>. [Feature #14245]
+
+[Object]
+
+  * Object#=~ is deprecated.  [Feature #15231]
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* These standard libraries have been promoted to default gems.
+
+  * e2mmap
+  * forwardable
+  * irb
+  * logger
+  * matrix
+  * mutex_m
+  * ostruct
+  * prime
+  * rexml
+  * rss
+  * shell
+  * sync
+  * thwait
+  * tracer
+
+[BigDecimal]
+
+  * The following methods are removed.
+
+    * BigDecimal.allocate
+    * BigDecimal.ver
+
+  * Every BigDecimal object is frozen. [Feature #13984]
+
+  * BigDecimal() parses the given string similar to Float().
+
+  * String#to_d parses the receiver string similar to String#to_f.
+
+  * BigDecimal.new will be removed in version 2.0.
+
+[Pathname]
+
+  * Pathname#read, Pathname#binread, Pathname#write, Pathname#binwrite,
+    Pathname#each_line and Pathname#readlines do not invoke external
+    commands even if the path starts with the pipe character <code>'|'</code>.
+    This follows [Feature #14245].
+
+=== Implementation improvements
+
+* Speedup Proc#call because we don't need to care about <code>$SAFE</code>
+  any more. [Feature #14318]
+
+  With +lc_fizzbuzz+ benchmark which uses Proc#call many times we can
+  measure x1.4 improvements.  [Bug #10212]
+
+* Speedup block.call where +block+ is passed block parameter. [Feature #14330]
+
+  Ruby 2.5 improves block passing performance. [Feature #14045]
+
+  Additionally, Ruby 2.6 improves the performance of passed block calling.
+
+* Introduce an initial implementation of a JIT (Just-in-time) compiler. [Feature #14235] [experimental]
+
+  * <tt>--jit</tt> command line option is added to enable JIT. <tt>--jit-verbose=1</tt>
+    is good for inspection.  See <tt>ruby --help</tt> for others.
+  * To generate machine code, this JIT compiler uses the C compiler used for building
+    the interpreter. Currently GCC, Clang, and Microsoft Visual C++ are supported for it.
+  * <tt>--disable-mjit-support</tt> option is added to configure. This is added for JIT debugging,
+    but if you get an error on building a header file for JIT, you can use this option to skip
+    building it as a workaround.
+  * rb_waitpid reimplemented on Unix-like platforms to maintain
+    compatibility with processes created for JIT [Bug #14867]
+
+* VM generator script renewal; makes the generated VM more optimized. [GH-1779]
+
+* Thread cache enabled for pthreads platforms (for Thread.new and
+  Thread.start).  [Feature #14757]
+
+* timer thread is eliminated for platforms with POSIX timers. [Misc #14937]
+
+* Transient Heap (theap) is supported. [Bug #14858] [Feature #14989]
+
+  theap is a managed heap for short-living memory objects. For example,
+  making a small and short-living Hash object is x2 faster. With rdoc benchmark,
+  we measured 6-7% performance improvement.
+
+* Native implementations (arm32, arm64, ppc64le, win32, win64, x86, amd64) of
+  coroutines to improve performance of Fiber significantly. [Feature #14739]
+
+=== Miscellaneous changes
+
+* On macOS, shared libraries no longer include a full version number of Ruby
+  in their names.  This eliminates the burden of each teeny upgrade on the
+  platform that users need to rebuild every extension library.
+
+  [Before]
+    * libruby.2.6.0.dylib
+    * libruby.2.6.dylib -> libruby.2.6.0.dylib
+    * libruby.dylib -> libruby.2.6.0.dylib
+
+  [After]
+    * libruby.2.6.dylib
+    * libruby.dylib -> libruby.2.6.dylib
+
+* Extracted misc/*.el files to https://github.com/ruby/elisp
diff --git a/doc/NEWS/NEWS-2.7.0 b/doc/NEWS/NEWS-2.7.0
new file mode 100644
index 0000000000..7607a473de
--- /dev/null
+++ b/doc/NEWS/NEWS-2.7.0
@@ -0,0 +1,845 @@
+# -*- rdoc -*-
+
+= NEWS for Ruby 2.7.0
+
+This document is a list of user visible feature changes made between
+releases except for bug fixes.
+
+Note that each entry is kept so brief that no reason behind or reference
+information is supplied with.  For a full list of changes with all
+sufficient information, see the ChangeLog file or Redmine
+(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>).
+
+== Changes since the 2.6.0 release
+
+=== Language changes
+
+==== Pattern matching
+
+* Pattern matching is introduced as an experimental feature. [Feature #14912]
+
+    case [0, [1, 2, 3]]
+    in [a, [b, *c]]
+      p a #=> 0
+      p b #=> 1
+      p c #=> [2, 3]
+    end
+
+    case {a: 0, b: 1}
+    in {a: 0, x: 1}
+      :unreachable
+    in {a: 0, b: var}
+      p var #=> 1
+    end
+
+    case -1
+    in 0 then :unreachable
+    in 1 then :unreachable
+    end #=> NoMatchingPatternError
+
+    json = <<END
+    {
+      "name": "Alice",
+      "age": 30,
+      "children": [{ "name": "Bob", "age": 2 }]
+    }
+    END
+
+    JSON.parse(json, symbolize_names: true) in {name: "Alice", children: [{name: name, age: age}]}
+
+    p name #=> "Bob"
+    p age  #=> 2
+
+    JSON.parse(json, symbolize_names: true) in {name: "Alice", children: [{name: "Charlie", age: age}]}
+    #=> NoMatchingPatternError
+
+* See the following slides for more details:
+  * https://speakerdeck.com/k_tsj/pattern-matching-new-feature-in-ruby-2-dot-7
+  * Note that the slides are slightly obsolete.
+
+* The warning against pattern matching can be suppressed with
+  {-W:no-experimental option}[#label-Warning+option].
+
+==== The spec of keyword arguments is changed towards 3.0
+
+* Automatic conversion of keyword arguments and positional arguments is
+  deprecated, and conversion will be removed in Ruby 3.  [Feature #14183]
+
+  * When a method call passes a Hash at the last argument, and when it
+    passes no keywords, and when the called method accepts keywords,
+    a warning is emitted.  To continue treating the hash as keywords,
+    add a double splat operator to avoid the warning and ensure
+    correct behavior in Ruby 3.
+
+      def foo(key: 42); end; foo({key: 42})   # warned
+      def foo(**kw);    end; foo({key: 42})   # warned
+      def foo(key: 42); end; foo(**{key: 42}) # OK
+      def foo(**kw);    end; foo(**{key: 42}) # OK
+
+  * When a method call passes keywords to a method that accepts keywords,
+    but it does not pass enough required positional arguments, the
+    keywords are treated as a final required positional argument, and a
+    warning is emitted.  Pass the argument as a hash instead of keywords
+    to avoid the warning and ensure correct behavior in Ruby 3.
+
+      def foo(h, **kw); end; foo(key: 42)      # warned
+      def foo(h, key: 42); end; foo(key: 42)   # warned
+      def foo(h, **kw); end; foo({key: 42})    # OK
+      def foo(h, key: 42); end; foo({key: 42}) # OK
+
+  * When a method accepts specific keywords but not a keyword splat, and
+    a hash or keywords splat is passed to the method that includes both
+    Symbol and non-Symbol keys, the hash will continue to be split, and
+    a warning will be emitted.  You will need to update the calling code
+    to pass separate hashes to ensure correct behavior in Ruby 3.
+
+      def foo(h={}, key: 42); end; foo("key" => 43, key: 42)   # warned
+      def foo(h={}, key: 42); end; foo({"key" => 43, key: 42}) # warned
+      def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
+
+  * If a method does not accept keywords, and is called with keywords,
+    the keywords are still treated as a positional hash, with no warning.
+    This behavior will continue to work in Ruby 3.
+
+      def foo(opt={});  end; foo( key: 42 )   # OK
+
+* Non-symbols are allowed as keyword argument keys if the method accepts
+  arbitrary keywords. [Feature #14183]
+
+  * Non-Symbol keys in a keyword arguments hash were prohibited in 2.6.0,
+    but are now allowed again.  [Bug #15658]
+
+      def foo(**kw); p kw; end; foo("str" => 1) #=> {"str"=>1}
+
+* <code>**nil</code> is allowed in method definitions to explicitly mark
+  that the method accepts no keywords. Calling such a method with keywords
+  will result in an ArgumentError. [Feature #14183]
+
+    def foo(h, **nil); end; foo(key: 1)       # ArgumentError
+    def foo(h, **nil); end; foo(**{key: 1})   # ArgumentError
+    def foo(h, **nil); end; foo("str" => 1)   # ArgumentError
+    def foo(h, **nil); end; foo({key: 1})     # OK
+    def foo(h, **nil); end; foo({"str" => 1}) # OK
+
+* Passing an empty keyword splat to a method that does not accept keywords
+  no longer passes an empty hash, unless the empty hash is necessary for
+  a required parameter, in which case a warning will be emitted.  Remove
+  the double splat to continue passing a positional hash.  [Feature #14183]
+
+    h = {}; def foo(*a) a end; foo(**h) # []
+    h = {}; def foo(a) a end; foo(**h)  # {} and warning
+    h = {}; def foo(*a) a end; foo(h)   # [{}]
+    h = {}; def foo(a) a end; foo(h)    # {}
+
+* Above warnings can be suppressed also with {-W:no-deprecated option}[#label-Warning+option].
+
+==== Numbered parameters
+
+* Numbered parameters as default block parameters are introduced. [Feature #4475]
+
+    [1, 2, 10].map { _1.to_s(16) }    #=> ["1", "2", "a"]
+    [[1, 2], [3, 4]].map { _1 + _2 }  #=> [3, 7]
+
+  You can still define a local variable named +_1+ and so on,
+  and that is honored when present, but renders a warning.
+
+    _1 = 0            #=> warning: `_1' is reserved for numbered parameter; consider another name
+    [1].each { p _1 } # prints 0 instead of 1
+
+==== proc/lambda without block is deprecated
+
+* Proc.new and Kernel#proc with no block in a method called with a block will
+  now display a warning.
+
+    def foo
+      proc
+    end
+    foo { puts "Hello" } #=> warning: Capturing the given block using Kernel#proc is deprecated; use `&block` instead
+
+  This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option].
+
+* Kernel#lambda with no block in a method called with a block raises an exception.
+
+    def bar
+      lambda
+    end
+    bar { puts "Hello" } #=> tried to create Proc object without a block (ArgumentError)
+
+==== Other miscellaneous changes
+
+* A beginless range is experimentally introduced.  It might be useful
+  in +case+, new call-sequence of the <code>Comparable#clamp</code>,
+  constants and DSLs.  [Feature #14799]
+
+     ary[..3]  # identical to ary[0..3]
+
+     case RUBY_VERSION
+     when ..."2.4" then puts "EOL"
+     # ...
+     end
+
+     age.clamp(..100)
+
+     where(sales: ..100)
+
+* Setting <code>$;</code> to a non-nil value will now display a warning. [Feature #14240]
+  This includes the usage in String#split.
+  This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option].
+
+* Setting <code>$,</code> to a non-nil value will now display a warning. [Feature #14240]
+  This includes the usage in Array#join.
+  This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option].
+
+* Quoted here-document identifiers must end within the same line.
+
+     <<"EOS
+     " # This had been warned since 2.4; Now it raises a SyntaxError
+     EOS
+
+* The flip-flop syntax deprecation is reverted. [Feature #5400]
+
+* Comment lines can be placed between fluent dot now.
+
+    foo
+      # .bar
+      .baz # => foo.baz
+
+* Calling a private method with a literal +self+ as the receiver
+  is now allowed. [Feature #11297] [Feature #16123]
+
+* Modifier rescue now operates the same for multiple assignment as single
+  assignment. [Bug #8279]
+
+    a, b = raise rescue [1, 2]
+    # Previously parsed as: (a, b = raise) rescue [1, 2]
+    # Now parsed as:         a, b = (raise rescue [1, 2])
+
+* +yield+ in singleton class syntax will now display a warning. This behavior
+  will soon be deprecated. [Feature #15575].
+
+   def foo
+     class << Object.new
+       yield #=> warning: `yield' in class syntax will not be supported from Ruby 3.0. [Feature #15575]
+     end
+   end
+   foo { p :ok }
+
+  This warning can be suppressed with {-W:no-deprecated option}[#label-Warning+option].
+
+* Argument forwarding by <code>(...)</code> is introduced. [Feature #16253]
+
+    def foo(...)
+      bar(...)
+    end
+
+  All arguments to +foo+ are forwarded to +bar+, including keyword and
+  block arguments.
+  Note that the parentheses are mandatory.  <code>bar ...</code> is parsed
+  as an endless range.
+
+* Access and setting of <code>$SAFE</code> will now always display a warning.
+  <code>$SAFE</code> will become a normal global variable in Ruby 3.0.  [Feature #16131]
+
+* <code>Object#{taint,untaint,trust,untrust}</code> and related functions in the C-API
+  no longer have an effect (all objects are always considered untainted), and will now
+  display a warning in verbose mode. This warning will be disabled even in non-verbose mode in
+  Ruby 3.0, and the methods and C functions will be removed in Ruby 3.2. [Feature #16131]
+
+* Refinements take place at Object#method and Module#instance_method. [Feature #15373]
+
+=== Command line options
+
+==== Warning option
+
+The +-W+ option has been extended with a following +:+, to manage categorized
+warnings.  [Feature #16345] [Feature #16420]
+
+* To suppress deprecation warnings:
+
+    $ ruby -e '$; = ""'
+    -e:1: warning: `$;' is deprecated
+
+    $ ruby -W:no-deprecated -e '$; = //'
+
+* It works with the +RUBYOPT+ environment variable:
+
+    $ RUBYOPT=-W:no-deprecated ruby -e '$; = //'
+
+* To suppress experimental feature warnings:
+
+    $ ruby -e '0 in a'
+    -e:1: warning: Pattern matching is experimental, and the behavior may change in future versions of Ruby!
+
+    $ ruby -W:no-experimental -e '0 in a'
+
+* To suppress both by using +RUBYOPT+, set space separated values:
+
+    $ RUBYOPT='-W:no-deprecated -W:no-experimental' ruby -e '($; = "") in a'
+
+See also Warning in {Core classes updates}[#label-Core+classes+updates+-28outstanding+ones+only-29].
+
+=== Core classes updates (outstanding ones only)
+
+[Array]
+
+  [New methods]
+
+    * Added Array#intersection. [Feature #16155]
+
+    * Added Array#minmax, with a faster implementation than Enumerable#minmax. [Bug #15929]
+
+[Comparable]
+
+  [Modified method]
+
+    * Comparable#clamp now accepts a Range argument. [Feature #14784]
+
+        -1.clamp(0..2) #=> 0
+         1.clamp(0..2) #=> 1
+         3.clamp(0..2) #=> 2
+        # With beginless and endless ranges:
+        -1.clamp(0..)  #=> 0
+         3.clamp(..2)  #=> 2
+
+
+[Complex]
+
+  [New method]
+
+    * Added Complex#<=>.
+      So <code>0 <=> 0i</code> will not raise NoMethodError. [Bug #15857]
+
+[Dir]
+
+  [Modified methods]
+
+    * Dir.glob and Dir.[] no longer allow NUL-separated glob pattern.
+      Use Array instead.  [Feature #14643]
+
+[Encoding]
+
+  [New encoding]
+
+    * Added new encoding CESU-8. [Feature #15931]
+
+[Enumerable]
+
+  [New methods]
+
+    * Added Enumerable#filter_map.  [Feature #15323]
+
+        [1, 2, 3].filter_map {|x| x.odd? ? x.to_s : nil } #=> ["1", "3"]
+
+    * Added Enumerable#tally.  [Feature #11076]
+
+        ["A", "B", "C", "B", "A"].tally #=> {"A"=>2, "B"=>2, "C"=>1}
+
+[Enumerator]
+
+  [New methods]
+
+    * Added Enumerator.produce to generate an Enumerator from any custom
+      data transformation.  [Feature #14781]
+
+        require "date"
+        dates = Enumerator.produce(Date.today, &:succ) #=> infinite sequence of dates
+        dates.detect(&:tuesday?) #=> next Tuesday
+
+    * Added Enumerator::Lazy#eager that generates a non-lazy enumerator
+      from a lazy enumerator.  [Feature #15901]
+
+        a = %w(foo bar baz)
+        e = a.lazy.map {|x| x.upcase }.map {|x| x + "!" }.eager
+        p e.class               #=> Enumerator
+        p e.map {|x| x + "?" }  #=> ["FOO!?", "BAR!?", "BAZ!?"]
+
+    * Added Enumerator::Yielder#to_proc so that a Yielder object
+      can be directly passed to another method as a block
+      argument.  [Feature #15618]
+
+    * Added Enumerator::Lazy#with_index be lazy
+      Previously, Enumerator::Lazy#with_index was not defined, so it
+      picked up the default implementation from Enumerator, which was
+      not lazy.  [Bug #7877]
+
+        ("a"..).lazy.with_index(1) { |it, index| puts "#{index}:#{it}" }.take(3).force
+        # => 1:a
+        #    2:b
+        #    3:c
+
+[Fiber]
+
+  [New method]
+
+    * Added Fiber#raise that behaves like Fiber#resume but raises an
+      exception on the resumed fiber.  [Feature #10344]
+
+[File]
+
+  [New method]
+
+    * Added File.absolute_path? to check whether a path is absolute or
+      not in a portable way. [Feature #15868]
+
+        File.absolute_path?("/foo")   # => true (on *nix)
+        File.absolute_path?("C:/foo") # => true (on Windows)
+        File.absolute_path?("foo")    # => false
+
+  [Modified method]
+
+    * File.extname now returns a dot string for names ending with a dot on
+      non-Windows platforms.  [Bug #15267]
+
+          File.extname("foo.") #=> "."
+
+[FrozenError]
+
+  [New method]
+
+    * Added FrozenError#receiver to return the frozen object on which
+      modification was attempted.  To set this object when raising
+      FrozenError in Ruby code, FrozenError.new accepts a +:receiver+
+      option.  [Feature #15751]
+
+[GC]
+
+  [New method]
+
+    * Added GC.compact method for compacting the heap.
+      This function compacts live objects in the heap so that fewer pages may
+      be used, and the heap may be more CoW (copy-on-write) friendly. [Feature #15626]
+
+      Details on the algorithm and caveats can be found here:
+      https://bugs.ruby-lang.org/issues/15626
+
+[IO]
+
+  [New method]
+
+    * Added IO#set_encoding_by_bom to check the BOM and set the external
+      encoding.  [Bug #15210]
+
+[Integer]
+
+  [Modified method]
+
+    * Integer#[] now supports range operations.  [Feature #8842]
+
+         0b01001101[2, 4]  #=> 0b0011
+         0b01001100[2..5]  #=> 0b0011
+         0b01001100[2...6] #=> 0b0011
+         #   ^^^^
+
+[Method]
+
+  [Modified method]
+
+    * Method#inspect shows more information. [Feature #14145]
+
+[Module]
+
+  [New methods]
+
+    * Added Module#const_source_location to retrieve the location where a
+      constant is defined.  [Feature #10771]
+
+    * Added Module#ruby2_keywords for marking a method as passing keyword
+      arguments through a regular argument splat, useful when delegating
+      all arguments to another method in a way that can be backwards
+      compatible with older Ruby versions.  [Bug #16154]
+
+  [Modified methods]
+
+    * Module#autoload? now takes an +inherit+ optional argument, like
+      Module#const_defined?.  [Feature #15777]
+
+    * Module#name now always returns a frozen String. The returned String is
+      always the same for a given Module. This change is
+      experimental. [Feature #16150]
+
+[NilClass / TrueClass / FalseClass]
+
+  [Modified methods]
+
+    * NilClass#to_s, TrueClass#to_s, and FalseClass#to_s now always return a
+      frozen String. The returned String is always the same for each of these
+      values. This change is experimental. [Feature #16150]
+
+[ObjectSpace::WeakMap]
+
+  [Modified method]
+
+    * ObjectSpace::WeakMap#[]= now accepts special objects as either key or
+      values.  [Feature #16035]
+
+[Proc]
+
+  [New method]
+
+    * Added Proc#ruby2_keywords for marking the proc as passing keyword
+      arguments through a regular argument splat, useful when delegating
+      all arguments to another method or proc in a way that can be backwards
+      compatible with older Ruby versions.  [Feature #16404]
+
+[Range]
+
+  [New method]
+
+    * Added Range#minmax, with a faster implementation than Enumerable#minmax.
+      It returns a maximum that now corresponds to Range#max. [Bug #15807]
+
+  [Modified method]
+
+    * Range#=== now uses Range#cover? for String arguments, too (in Ruby 2.6, it was
+      changed from Range#include? for all types except strings). [Bug #15449]
+
+
+[RubyVM]
+
+  [Removed method]
+
+    * +RubyVM.resolve_feature_path+ moved to
+      <code>$LOAD_PATH.resolve_feature_path</code>.  [Feature #15903] [Feature #15230]
+
+[String]
+
+  [Unicode]
+
+    * Update Unicode version and Emoji version from 11.0.0 to
+      12.0.0.  [Feature #15321]
+
+    * Update Unicode version to 12.1.0, adding support for
+      U+32FF SQUARE ERA NAME REIWA.  [Feature #15195]
+
+    * Update Unicode Emoji version to 12.1. [Feature #16272]
+
+[Symbol]
+
+  [New methods]
+
+    * Added Symbol#start_with? and Symbol#end_with? methods.  [Feature #16348]
+
+[Time]
+
+  [New methods]
+
+    * Added Time#ceil method.  [Feature #15772]
+
+    * Added Time#floor method.  [Feature #15653]
+
+  [Modified method]
+
+    * Time#inspect is separated from Time#to_s and it shows
+      the time's sub second.  [Feature #15958]
+
+[UnboundMethod]
+
+  [New method]
+
+    * Added UnboundMethod#bind_call method.  [Feature #15955]
+
+      <code>umethod.bind_call(obj, ...)</code> is semantically equivalent
+      to <code>umethod.bind(obj).call(...)</code>.  This idiom is used in
+      some libraries to call a method that is overridden.  The added
+      method does the same without allocation of an intermediate Method
+      object.
+
+          class Foo
+            def add_1(x)
+              x + 1
+            end
+          end
+          class Bar < Foo
+            def add_1(x) # override
+              x + 2
+            end
+          end
+
+          obj = Bar.new
+          p obj.add_1(1) #=> 3
+          p Foo.instance_method(:add_1).bind(obj).call(1) #=> 2
+          p Foo.instance_method(:add_1).bind_call(obj, 1) #=> 2
+
+[Warning]
+
+  [New methods]
+
+    * Added Warning.[] and Warning.[]= to manage emitting/suppressing
+      some categories of warnings.  [Feature #16345] [Feature #16420]
+
+[$LOAD_PATH]
+
+  [New method]
+
+    * Added <code>$LOAD_PATH.resolve_feature_path</code>.  [Feature #15903] [Feature #15230]
+
+=== Stdlib updates (outstanding ones only)
+
+[Bundler]
+
+  * Upgrade to Bundler 2.1.2.
+    See https://github.com/bundler/bundler/releases/tag/v2.1.2
+
+[CGI]
+
+  * CGI.escapeHTML becomes 2~5x faster when there is at least one escaped character.
+    See https://github.com/ruby/ruby/pull/2226
+
+[CSV]
+
+  * Upgrade to 3.1.2.
+    See https://github.com/ruby/csv/blob/master/NEWS.md.
+
+[Date]
+
+  * Date.jisx0301, Date#jisx0301, and Date.parse support the new Japanese
+    era.  [Feature #15742]
+
+[Delegator]
+
+  * Object#DelegateClass accepts a block and module_evals it in the context
+    of the returned class, similar to Class.new and Struct.new.
+
+[ERB]
+
+  * Prohibit marshaling ERB instance.
+
+[IRB]
+
+  * Introduce syntax highlighting inspired by the Pry gem to Binding#irb
+    source lines, REPL input, and inspect output of some core-class objects.
+
+  * Introduce multiline editing mode provided by Reline.
+
+  * Show documentation when completion.
+
+  * Enable auto indent and save/load history by default.
+
+[JSON]
+
+  * Upgrade to 2.3.0.
+
+[Net::FTP]
+
+  * Add Net::FTP#features to check available features, and Net::FTP#option to
+    enable/disable each of them.  [Feature #15964]
+
+[Net::HTTP]
+
+  * Add +ipaddr+ optional parameter to Net::HTTP#start to replace the address for
+    the TCP/IP connection. [Feature #5180]
+
+[Net::IMAP]
+
+  * Add Server Name Indication (SNI) support.  [Feature #15594]
+
+[open-uri]
+
+  * Warn open-uri's "open" method at Kernel.
+    Use URI.open instead.  [Misc #15893]
+
+  * The default charset of "text/*" media type is UTF-8 instead of
+    ISO-8859-1.  [Bug #15933]
+
+[OptionParser]
+
+  * Now show "Did you mean?" for unknown options.  [Feature #16256]
+
+    test.rb:
+
+      require "optparse"
+      OptionParser.new do |opts|
+        opts.on("-f", "--foo", "foo") {|v| }
+        opts.on("-b", "--bar", "bar") {|v| }
+        opts.on("-c", "--baz", "baz") {|v| }
+      end.parse!
+
+    example:
+
+      $ ruby test.rb --baa
+      Traceback (most recent call last):
+      test.rb:7:in `<main>': invalid option: --baa (OptionParser::InvalidOption)
+      Did you mean?  baz
+                     bar
+
+[Pathname]
+
+  * Pathname.glob now delegates 3 arguments to Dir.glob
+    to accept +base+ keyword. [Feature #14405]
+
+[Racc]
+
+  * Merge 1.4.15 from upstream repository and added cli of racc.
+
+[Reline]
+
+  * New stdlib that is compatible with the readline stdlib but is
+    implemented in pure Ruby. It also provides a multiline editing mode.
+
+[REXML]
+
+  * Upgrade to 3.2.3.
+    See https://github.com/ruby/rexml/blob/master/NEWS.md.
+
+[RSS]
+
+  * Upgrade to RSS 0.2.8.
+    See https://github.com/ruby/rss/blob/master/NEWS.md.
+
+[RubyGems]
+
+  * Upgrade to RubyGems 3.1.2.
+    * https://github.com/rubygems/rubygems/releases/tag/v3.1.0
+    * https://github.com/rubygems/rubygems/releases/tag/v3.1.1
+    * https://github.com/rubygems/rubygems/releases/tag/v3.1.2
+
+[StringScanner]
+
+  * Upgrade to 1.0.3.
+    See https://github.com/ruby/strscan/blob/master/NEWS.md.
+
+=== Compatibility issues (excluding feature bug fixes)
+
+* The following libraries are no longer bundled gems.
+  Install corresponding gems to use these features.
+  * CMath (cmath gem)
+  * Scanf (scanf gem)
+  * Shell (shell gem)
+  * Synchronizer (sync gem)
+  * ThreadsWait (thwait gem)
+  * E2MM (e2mmap gem)
+
+[Proc]
+  * The Proc#to_s format was changed. [Feature #16101]
+
+[Range]
+  * Range#minmax used to iterate on the range to determine the maximum.
+    It now uses the same algorithm as Range#max. In rare cases (e.g.
+    ranges of Floats or Strings), this may yield different results. [Bug #15807]
+
+=== Stdlib compatibility issues (excluding feature bug fixes)
+
+* Promote stdlib to default gems
+  * The following default gems were published on rubygems.org
+    * benchmark
+    * cgi
+    * delegate
+    * getoptlong
+    * net-pop
+    * net-smtp
+    * open3
+    * pstore
+    * readline
+    * readline-ext
+    * singleton
+  * The following default gems were only promoted at ruby-core,
+    but not yet published on rubygems.org.
+    * monitor
+    * observer
+    * timeout
+    * tracer
+    * uri
+    * yaml
+* The <tt>did_you_mean</tt> gem has been promoted up to a default gem from a bundled gem
+
+[pathname]
+
+  * Kernel#Pathname when called with a Pathname argument now returns
+    the argument instead of creating a new Pathname. This is more
+    similar to other Kernel methods, but can break code that modifies
+    the return value and expects the argument not to be modified.
+
+[profile.rb, Profiler__]
+
+  * Removed from standard library. It was unmaintained since Ruby 2.0.0.
+
+=== C API updates
+
+* Many <code>*_kw</code> functions have been added for setting whether
+  the final argument being passed should be treated as keywords. You
+  may need to switch to these functions to avoid keyword argument
+  separation warnings, and to ensure correct behavior in Ruby 3.
+
+* The <code>:</code> character in rb_scan_args format string is now
+  treated as keyword arguments. Passing a positional hash instead of
+  keyword arguments will emit a deprecation warning.
+
+* C API declarations with +ANYARGS+ are changed not to use +ANYARGS+.
+  See https://github.com/ruby/ruby/pull/2404
+
+=== Implementation improvements
+
+[Fiber]
+
+  * Allow selecting different coroutine implementations by using
+    +--with-coroutine=+, e.g.
+
+         $ ./configure --with-coroutine=ucontext
+         $ ./configure --with-coroutine=copy
+
+  * Replace previous stack cache with fiber pool cache. The fiber pool
+    allocates many stacks in a single memory region. Stack allocation
+    becomes O(log N) and fiber creation is amortized O(1). Around 10x
+    performance improvement was measured in micro-benchmarks.
+    https://github.com/ruby/ruby/pull/2224
+
+[File]
+  * File.realpath now uses realpath(3) on many platforms, which can
+    significantly improve performance. [Feature #15797]
+
+[Hash]
+  * Change data structure of small Hash objects. [Feature #15602]
+
+[Monitor]
+  * Monitor class is written in C-extension. [Feature #16255]
+
+[Thread]
+
+  * VM stack memory allocation is now combined with native thread stack,
+    improving thread allocation performance and reducing allocation related
+    failures. Around 10x performance improvement was measured in micro-benchmarks.
+
+[JIT]
+
+  * JIT-ed code is recompiled to less-optimized code when an optimization assumption is invalidated.
+
+  * Method inlining is performed when a method is considered as pure.
+    This optimization is still experimental and many methods are NOT considered as pure yet.
+
+  * The default value of +--jit-max-cache+ is changed from 1,000 to 100.
+
+  * The default value of +--jit-min-calls+ is changed from 5 to 10,000.
+
+[RubyVM]
+
+  * Per-call-site method cache, which has been there since around 1.9, was
+    improved: cache hit rate raised from 89% to 94%.
+    See https://github.com/ruby/ruby/pull/2583
+
+[RubyVM::InstructionSequence]
+
+  * RubyVM::InstructionSequence#to_binary method generates compiled binary.
+    The binary size is reduced. [Feature #16163]
+
+=== Miscellaneous changes
+
+* Support for IA64 architecture has been removed. Hardware for testing was
+  difficult to find, native fiber code is difficult to implement, and it added
+  non-trivial complexity to the interpreter. [Feature #15894]
+
+* Require compilers to support C99. [Misc #15347]
+
+  * Details of our dialect: https://bugs.ruby-lang.org/projects/ruby-master/wiki/C99
+
+* Ruby's upstream repository is changed from Subversion to Git.
+
+  * https://git.ruby-lang.org/ruby.git
+
+  * RUBY_REVISION class is changed from Integer to String.
+
+  * RUBY_DESCRIPTION includes Git revision instead of Subversion's one.
+
+* Support built-in methods in Ruby with the <code>_\_builtin_</code> syntax. [Feature #16254]
+
+  Some methods are defined in *.rb (such as trace_point.rb).
+  For example, it is easy to define a method which accepts keyword arguments.
diff --git a/doc/NEWS/NEWS-3.0.0.md b/doc/NEWS/NEWS-3.0.0.md
new file mode 100644
index 0000000000..00c26fe585
--- /dev/null
+++ b/doc/NEWS/NEWS-3.0.0.md
@@ -0,0 +1,817 @@
+# NEWS for Ruby 3.0.0
+
+This document is a list of user visible feature changes
+since the **2.7.0** release, except for bug fixes.
+
+Note that each entry is kept to a minimum, see links for details.
+
+## Language changes
+
+* Keyword arguments are now separated from positional arguments.
+  Code that resulted in deprecation warnings in Ruby 2.7 will now
+  result in ArgumentError or different behavior. [[Feature #14183]]
+
+* Procs accepting a single rest argument and keywords are no longer
+  subject to autosplatting.  This now matches the behavior of Procs
+  accepting a single rest argument and no keywords.
+  [[Feature #16166]]
+
+    ```ruby
+    pr = proc{|*a, **kw| [a, kw]}
+
+    pr.call([1])
+    # 2.7 => [[1], {}]
+    # 3.0 => [[[1]], {}]
+
+    pr.call([1, {a: 1}])
+    # 2.7 => [[1], {:a=>1}] # and deprecation warning
+    # 3.0 => [[[1, {:a=>1}]], {}]
+    ```
+
+* Arguments forwarding (`...`) now supports leading arguments.
+  [[Feature #16378]]
+
+    ```ruby
+    def method_missing(meth, ...)
+      send(:"do_#{meth}", ...)
+    end
+    ```
+
+* Pattern matching (`case/in`) is no longer experimental. [[Feature #17260]]
+
+* One-line pattern matching is redesigned.  [EXPERIMENTAL]
+
+    * `=>` is added. It can be used like a rightward assignment.
+      [[Feature #17260]]
+
+        ```ruby
+        0 => a
+        p a #=> 0
+
+        {b: 0, c: 1} => {b:}
+        p b #=> 0
+        ```
+
+    * `in` is changed to return `true` or `false`. [[Feature #17371]]
+
+        ```ruby
+        # version 3.0
+        0 in 1 #=> false
+
+        # version 2.7
+        0 in 1 #=> raise NoMatchingPatternError
+        ```
+
+* Find-pattern is added.  [EXPERIMENTAL]
+  [[Feature #16828]]
+
+    ```ruby
+    case ["a", 1, "b", "c", 2, "d", "e", "f", 3]
+    in [*pre, String => x, String => y, *post]
+      p pre  #=> ["a", 1]
+      p x    #=> "b"
+      p y    #=> "c"
+      p post #=> [2, "d", "e", "f", 3]
+    end
+    ```
+
+* Endless method definition is added.  [EXPERIMENTAL]
+  [[Feature #16746]]
+
+    ```ruby
+    def square(x) = x * x
+    ```
+
+* Interpolated String literals are no longer frozen when
+  `# frozen-string-literal: true` is used. [[Feature #17104]]
+
+* Magic comment `shareable_constant_value` added to freeze constants.
+  See {Magic Comments}[rdoc-ref:syntax/comments.rdoc@Magic+Comments] for more details.
+  [[Feature #17273]]
+
+* A {static analysis}[rdoc-label:label-Static+analysis] foundation is
+  introduced.
+    * {RBS}[rdoc-label:label-RBS] is introduced. It is a type definition
+      language for Ruby programs.
+    * {TypeProf}[rdoc-label:label-TypeProf] is experimentally bundled. It is a
+      type analysis tool for Ruby programs.
+
+* Deprecation warnings are no longer shown by default (since Ruby 2.7.2).
+  Turn them on with `-W:deprecated` (or with `-w` to show other warnings too).
+  [[Feature #16345]]
+
+* `$SAFE` and `$KCODE` are now normal global variables with no special behavior.
+  C-API methods related to `$SAFE` have been removed.
+  [[Feature #16131]] [[Feature #17136]]
+
+* yield in singleton class definitions in methods is now a SyntaxError
+  instead of a warning. yield in a class definition outside of a method
+  is now a SyntaxError instead of a LocalJumpError.  [[Feature #15575]]
+
+* When a class variable is overtaken by the same definition in an
+  ancestor class/module, a RuntimeError is now raised (previously,
+  it only issued a warning in verbose mode).  Additionally, accessing a
+  class variable from the toplevel scope is now a RuntimeError.
+  [[Bug #14541]]
+
+* Assigning to a numbered parameter is now a SyntaxError instead of
+  a warning.
+
+## Command line options
+
+### `--help` option
+
+When the environment variable `RUBY_PAGER` or `PAGER` is present and has
+a non-empty value, and the standard input and output are tty, the `--help`
+option shows the help message via the pager designated by the value.
+[[Feature #16754]]
+
+### `--backtrace-limit` option
+
+The `--backtrace-limit` option limits the maximum length of a backtrace.
+[[Feature #8661]]
+
+## Core classes updates
+
+Outstanding ones only.
+
+* Array
+
+    * The following methods now return Array instances instead of
+      subclass instances when called on subclass instances:
+      [[Bug #6087]]
+
+        * Array#drop
+        * Array#drop_while
+        * Array#flatten
+        * Array#slice!
+        * Array#slice / Array#[]
+        * Array#take
+        * Array#take_while
+        * Array#uniq
+        * Array#*
+
+    * Can be sliced with Enumerator::ArithmeticSequence
+
+        ```ruby
+        dirty_data = ['--', 'data1', '--', 'data2', '--', 'data3']
+        dirty_data[(1..).step(2)] # take each second element
+        # => ["data1", "data2", "data3"]
+        ```
+
+* Binding
+
+    * Binding#eval when called with one argument will use `"(eval)"`
+      for `__FILE__` and `1` for `__LINE__` in the evaluated code.
+      [[Bug #4352]] [[Bug #17419]]
+
+* ConditionVariable
+
+    * ConditionVariable#wait may now invoke the `block`/`unblock` scheduler
+      hooks in a non-blocking context. [[Feature #16786]]
+
+* Dir
+
+    * Dir.glob and Dir.[] now sort the results by default, and
+      accept the `sort:` keyword option.  [[Feature #8709]]
+
+* ENV
+
+    * ENV.except has been added, which returns a hash excluding the
+      given keys and their values.  [[Feature #15822]]
+
+    * Windows: Read ENV names and values as UTF-8 encoded Strings
+      [[Feature #12650]]
+
+* Encoding
+
+    * Added new encoding IBM720.  [[Feature #16233]]
+
+    * Changed default for Encoding.default_external to UTF-8 on Windows
+      [[Feature #16604]]
+
+* Fiber
+
+    * Fiber.new(blocking: true/false) allows you to create non-blocking
+      execution contexts. [[Feature #16786]]
+
+    * Fiber#blocking? tells whether the fiber is non-blocking. [[Feature #16786]]
+
+    * Fiber#backtrace and Fiber#backtrace_locations provide per-fiber backtrace.
+      [[Feature #16815]]
+
+    * The limitation of Fiber#transfer is relaxed. [[Bug #17221]]
+
+* GC
+
+    * GC.auto_compact= and GC.auto_compact have been added to control
+      when compaction runs.  Setting `auto_compact=` to `true` will cause
+      compaction to occur during major collections.  At the moment,
+      compaction adds significant overhead to major collections, so please
+      test first!  [[Feature #17176]]
+
+* Hash
+
+    * Hash#transform_keys and Hash#transform_keys! now accept a hash that maps
+      keys to new keys.  [[Feature #16274]]
+
+    * Hash#except has been added, which returns a hash excluding the
+      given keys and their values.  [[Feature #15822]]
+
+* IO
+
+    * IO#nonblock? now defaults to `true`. [[Feature #16786]]
+
+    * IO#wait_readable, IO#wait_writable, IO#read, IO#write and other
+      related methods (e.g. IO#puts, IO#gets) may invoke the scheduler hook
+      `#io_wait(io, events, timeout)` in a non-blocking execution context.
+      [[Feature #16786]]
+
+* Kernel
+
+    * Kernel#clone when called with the `freeze: false` keyword will call
+      `#initialize_clone` with the `freeze: false` keyword.
+      [[Bug #14266]]
+
+    * Kernel#clone when called with the `freeze: true` keyword will call
+      `#initialize_clone` with the `freeze: true` keyword, and will
+      return a frozen copy even if the receiver is unfrozen.
+      [[Feature #16175]]
+
+    * Kernel#eval when called with two arguments will use `"(eval)"`
+      for `__FILE__` and `1` for `__LINE__` in the evaluated code.
+      [[Bug #4352]]
+
+    * Kernel#lambda now warns if called without a literal block.
+      [[Feature #15973]]
+
+    * Kernel.sleep invokes the scheduler hook `#kernel_sleep(...)` in a
+      non-blocking execution context. [[Feature #16786]]
+
+* Module
+
+    * Module#include and Module#prepend now affect classes and modules
+      that have already included or prepended the receiver, mirroring the
+      behavior if the arguments were included in the receiver before
+      the other modules and classes included or prepended the receiver.
+      [[Feature #9573]]
+
+        ```ruby
+        class C; end
+        module M1; end
+        module M2; end
+        C.include M1
+        M1.include M2
+        p C.ancestors #=> [C, M1, M2, Object, Kernel, BasicObject]
+        ```
+
+    * Module#public, Module#protected, Module#private, Module#public_class_method,
+      Module#private_class_method, toplevel "private" and "public" methods
+      now accept single array argument with a list of method names. [[Feature #17314]]
+
+    * Module#attr_accessor, Module#attr_reader, Module#attr_writer and Module#attr
+      methods now return an array of defined method names as symbols.
+      [[Feature #17314]]
+
+    * Module#alias_method now returns the defined alias as a symbol.
+      [[Feature #17314]]
+
+* Mutex
+
+    * `Mutex` is now acquired per-`Fiber` instead of per-`Thread`. This change
+      should be compatible for essentially all usages and avoids blocking when
+      using a scheduler. [[Feature #16792]]
+
+* Proc
+
+    * Proc#== and Proc#eql? are now defined and will return true for
+      separate Proc instances if the procs were created from the same block.
+      [[Feature #14267]]
+
+* Queue / SizedQueue
+
+    * Queue#pop, SizedQueue#push and related methods may now invoke the
+      `block`/`unblock` scheduler hooks in a non-blocking context.
+      [[Feature #16786]]
+
+* Ractor
+
+    * New class added to enable parallel execution. See rdoc-ref:ractor.md for
+      more details.
+
+* Random
+
+    * `Random::DEFAULT` now refers to the `Random` class instead of being a `Random` instance,
+      so it can work with `Ractor`.
+      [[Feature #17322]]
+
+    * `Random::DEFAULT` is deprecated since its value is now confusing and it is no longer global,
+      use `Kernel.rand`/`Random.rand` directly, or create a `Random` instance with `Random.new` instead.
+      [[Feature #17351]]
+
+
+* String
+
+    * The following methods now return or yield String instances
+      instead of subclass instances when called on subclass instances:
+      [[Bug #10845]]
+
+        * String#*
+        * String#capitalize
+        * String#center
+        * String#chomp
+        * String#chop
+        * String#delete
+        * String#delete_prefix
+        * String#delete_suffix
+        * String#downcase
+        * String#dump
+        * String#each_char
+        * String#each_grapheme_cluster
+        * String#each_line
+        * String#gsub
+        * String#ljust
+        * String#lstrip
+        * String#partition
+        * String#reverse
+        * String#rjust
+        * String#rpartition
+        * String#rstrip
+        * String#scrub
+        * String#slice!
+        * String#slice / String#[]
+        * String#split
+        * String#squeeze
+        * String#strip
+        * String#sub
+        * String#succ / String#next
+        * String#swapcase
+        * String#tr
+        * String#tr_s
+        * String#upcase
+
+* Symbol
+
+    * Symbol#to_proc now returns a lambda Proc.  [[Feature #16260]]
+
+    * Symbol#name has been added, which returns the name of the symbol
+      if it is named.  The returned string is frozen.  [[Feature #16150]]
+
+* Fiber
+
+    * Introduce Fiber.set_scheduler for intercepting blocking operations and
+      Fiber.scheduler for accessing the current scheduler. See
+      rdoc-ref:fiber.md for more details about what operations are supported and
+      how to implement the scheduler hooks. [[Feature #16786]]
+
+    * Fiber.blocking? tells whether the current execution context is
+      blocking. [[Feature #16786]]
+
+    * Thread#join invokes the scheduler hooks `block`/`unblock` in a
+      non-blocking execution context. [[Feature #16786]]
+
+* Thread
+
+    * Thread.ignore_deadlock accessor has been added for disabling the
+      default deadlock detection, allowing the use of signal handlers to
+      break deadlock. [[Bug #13768]]
+
+* Warning
+
+    * Warning#warn now supports a category keyword argument.
+      [[Feature #17122]]
+
+## Stdlib updates
+
+Outstanding ones only.
+
+* BigDecimal
+
+    * Update to BigDecimal 3.0.0
+
+    * This version is Ractor compatible.
+
+* Bundler
+
+    * Update to Bundler 2.2.3
+
+* CGI
+
+    * Update to 0.2.0
+
+    * This version is Ractor compatible.
+
+* CSV
+
+    * Update to CSV 3.1.9
+
+* Date
+
+    * Update to Date 3.1.1
+
+    * This version is Ractor compatible.
+
+* Digest
+
+    * Update to Digest 3.0.0
+
+    * This version is Ractor compatible.
+
+* Etc
+
+    * Update to Etc 1.2.0
+
+    * This version is Ractor compatible.
+
+* Fiddle
+
+    * Update to Fiddle 1.0.5
+
+* IRB
+
+    * Update to IRB 1.2.6
+
+* JSON
+
+    * Update to JSON 2.5.0
+
+    * This version is Ractor compatible.
+
+* Set
+
+    * Update to set 1.0.0
+
+    * SortedSet has been removed for dependency and performance reasons.
+
+    * Set#join is added as a shorthand for `.to_a.join`.
+
+    * Set#<=> is added.
+
+* Socket
+
+    * Add :connect_timeout to TCPSocket.new [[Feature #17187]]
+
+* Net::HTTP
+
+    * Net::HTTP#verify_hostname= and Net::HTTP#verify_hostname have been
+      added to skip hostname verification.  [[Feature #16555]]
+
+    * Net::HTTP.get, Net::HTTP.get_response, and Net::HTTP.get_print
+      can take the request headers as a Hash in the second argument when the
+      first argument is a URI.  [[Feature #16686]]
+
+* Net::SMTP
+
+    * Add SNI support.
+
+    * Net::SMTP.start arguments are keyword arguments.
+
+    * TLS should not check the host name by default.
+
+* OpenStruct
+
+    * Initialization is no longer lazy. [[Bug #12136]]
+
+    * Builtin methods can now be overridden safely. [[Bug #15409]]
+
+    * Implementation uses only methods ending with `!`.
+
+    * Ractor compatible.
+
+    * Improved support for YAML. [[Bug #8382]]
+
+    * Use officially discouraged. Read OpenStruct@Caveats section.
+
+* Pathname
+
+    * Ractor compatible.
+
+* Psych
+
+    * Update to Psych 3.3.0
+
+    * This version is Ractor compatible.
+
+* Reline
+
+    * Update to Reline 0.1.5
+
+* RubyGems
+
+    * Update to RubyGems 3.2.3
+
+* StringIO
+
+    * Update to StringIO 3.0.0
+
+    * This version is Ractor compatible.
+
+* StringScanner
+
+    * Update to StringScanner 3.0.0
+
+    * This version is Ractor compatible.
+
+## Compatibility issues
+
+Excluding feature bug fixes.
+
+* Regexp literals and all Range objects are frozen. [[Feature #8948]] [[Feature #16377]] [[Feature #15504]]
+
+    ```ruby
+    /foo/.frozen? #=> true
+    (42...).frozen? # => true
+    ```
+
+* EXPERIMENTAL: Hash#each consistently yields a 2-element array. [[Bug #12706]]
+
+    * Now `{ a: 1 }.each(&->(k, v) { })` raises an ArgumentError
+      due to lambda's arity check.
+
+* When writing to STDOUT redirected to a closed pipe, no broken pipe
+  error message will be shown now.  [[Feature #14413]]
+
+* `TRUE`/`FALSE`/`NIL` constants are no longer defined.
+
+* Integer#zero? overrides Numeric#zero? for optimization.  [[Misc #16961]]
+
+* Enumerable#grep and Enumerable#grep_v when passed a Regexp and no block no longer modify
+  Regexp.last_match. [[Bug #17030]]
+
+* Requiring 'open-uri' no longer redefines `Kernel#open`.
+  Call `URI.open` directly or `use URI#open` instead. [[Misc #15893]]
+
+* SortedSet has been removed for dependency and performance reasons.
+
+## Stdlib compatibility issues
+
+* Default gems
+
+    * The following libraries are promoted to default gems from stdlib.
+
+        * English
+        * abbrev
+        * base64
+        * drb
+        * debug
+        * erb
+        * find
+        * net-ftp
+        * net-http
+        * net-imap
+        * net-protocol
+        * open-uri
+        * optparse
+        * pp
+        * prettyprint
+        * resolv-replace
+        * resolv
+        * rinda
+        * set
+        * securerandom
+        * shellwords
+        * tempfile
+        * tmpdir
+        * time
+        * tsort
+        * un
+        * weakref
+
+    * The following extensions are promoted to default gems from stdlib.
+
+        * digest
+        * io-nonblock
+        * io-wait
+        * nkf
+        * pathname
+        * syslog
+        * win32ole
+
+* Bundled gems
+
+    * net-telnet and xmlrpc have been removed from the bundled gems.
+      If you are interested in maintaining them, please comment on
+      your plan to https://github.com/ruby/xmlrpc
+      or https://github.com/ruby/net-telnet.
+
+* SDBM has been removed from the Ruby standard library. [[Bug #8446]]
+
+    * The issues of sdbm will be handled at https://github.com/ruby/sdbm
+
+* WEBrick has been removed from the Ruby standard library. [[Feature #17303]]
+
+    * The issues of WEBrick will be handled at https://github.com/ruby/webrick
+
+## C API updates
+
+* C API functions related to `$SAFE` have been removed.
+  [[Feature #16131]]
+
+* C API header file `ruby/ruby.h` was split. [[GH-2991]]
+
+    This should have no impact on extension libraries,
+    but users might experience slow compilations.
+
+* Memory view interface [EXPERIMENTAL]
+
+    * The memory view interface is a C-API set to exchange a raw memory area,
+      such as a numeric array or a bitmap image, between extension libraries.
+      The extension libraries can share also the metadata of the memory area
+      that consists of the shape, the element format, and so on.
+      Using these kinds of metadata, the extension libraries can share even
+      a multidimensional array appropriately.
+      This feature is designed by referring to Python's buffer protocol.
+      [[Feature #13767]] [[Feature #14722]]
+
+* Ractor related C APIs are introduced (experimental) in "include/ruby/ractor.h".
+
+## Implementation improvements
+
+* New method cache mechanism for Ractor. [[Feature #16614]]
+
+    * Inline method caches pointed from ISeq can be accessed by multiple Ractors
+      in parallel and synchronization is needed even for method caches. However,
+      such synchronization can be overhead so introducing new inline method cache
+      mechanisms, (1) Disposable inline method cache (2) per-Class method cache
+      and (3) new invalidation mechanism. (1) can avoid per-method call
+      synchronization because it only uses atomic operations.
+      See the ticket for more details.
+
+* The number of hashes allocated when using a keyword splat in
+  a method call has been reduced to a maximum of 1, and passing
+  a keyword splat to a method that accepts specific keywords
+  does not allocate a hash.
+
+* `super` is optimized when the same type of method is called in the previous call
+  if it's not refinements or an attr reader or writer.
+
+### JIT
+
+* Performance improvements of JIT-ed code
+
+    * Microarchitectural optimizations
+
+        * Native functions shared by multiple methods are deduplicated on JIT compaction.
+
+        * Decrease code size of hot paths by some optimizations and partitioning cold paths.
+
+    * Instance variables
+
+        * Eliminate some redundant checks.
+
+        * Skip checking a class and a object multiple times in a method when possible.
+
+        * Optimize accesses in some core classes like Hash and their subclasses.
+
+    * Method inlining support for some C methods
+
+        * `Kernel`: `#class`, `#frozen?`
+
+        * `Integer`: `#-@`, `#~`, `#abs`, `#bit_length`, `#even?`, `#integer?`, `#magnitude`,
+          `#odd?`, `#ord`, `#to_i`, `#to_int`, `#zero?`
+
+        * `Struct`: reader methods for 10th or later members
+
+    * Constant references are inlined.
+
+    * Always generate appropriate code for `==`, `nil?`, and `!` calls depending on
+      a receiver class.
+
+    * Reduce the number of PC accesses on branches and method returns.
+
+    * Optimize C method calls a little.
+
+* Compilation process improvements
+
+    * It does not keep temporary files in /tmp anymore.
+
+    * Throttle GC and compaction of JIT-ed code.
+
+    * Avoid GC-ing JIT-ed code when not necessary.
+
+    * GC-ing JIT-ed code is executed in a background thread.
+
+    * Reduce the number of locks between Ruby and JIT threads.
+
+## Static analysis
+
+### RBS
+
+* RBS is a new language for type definition of Ruby programs.
+  It allows writing types of classes and modules with advanced
+  types including union types, overloading, generics, and
+  _interface types_ for duck typing.
+
+* Ruby ships with type definitions for core/stdlib classes.
+
+* `rbs` gem is bundled to load and process RBS files.
+
+### TypeProf
+
+* TypeProf is a type analysis tool for Ruby code based on abstract interpretation.
+
+    * It reads non-annotated Ruby code, tries inferring its type signature, and prints
+      the analysis result in RBS format.
+
+    * Though it supports only a subset of the Ruby language yet, we will continuously
+      improve the coverage of language features, analysis performance, and usability.
+
+```ruby
+# test.rb
+def foo(x)
+  if x > 10
+    x.to_s
+  else
+    nil
+  end
+end
+
+foo(42)
+```
+
+```
+$ typeprof test.rb
+# Classes
+class Object
+  def foo : (Integer) -> String?
+end
+```
+
+## Miscellaneous changes
+
+* Methods using `ruby2_keywords` will no longer keep empty keyword
+  splats, those are now removed just as they are for methods not
+  using `ruby2_keywords`.
+
+* When an exception is caught in the default handler, the error
+  message and backtrace are printed in order from the innermost.
+  [[Feature #8661]]
+
+* Accessing an uninitialized instance variable no longer emits a
+  warning in verbose mode. [[Feature #17055]]
+
+[Bug #4352]:      https://bugs.ruby-lang.org/issues/4352
+[Bug #6087]:      https://bugs.ruby-lang.org/issues/6087
+[Bug #8382]:      https://bugs.ruby-lang.org/issues/8382
+[Bug #8446]:      https://bugs.ruby-lang.org/issues/8446
+[Feature #8661]:  https://bugs.ruby-lang.org/issues/8661
+[Feature #8709]:  https://bugs.ruby-lang.org/issues/8709
+[Feature #8948]:  https://bugs.ruby-lang.org/issues/8948
+[Feature #9573]:  https://bugs.ruby-lang.org/issues/9573
+[Bug #10845]:     https://bugs.ruby-lang.org/issues/10845
+[Bug #12136]:     https://bugs.ruby-lang.org/issues/12136
+[Feature #12650]: https://bugs.ruby-lang.org/issues/12650
+[Bug #12706]:     https://bugs.ruby-lang.org/issues/12706
+[Feature #13767]: https://bugs.ruby-lang.org/issues/13767
+[Bug #13768]:     https://bugs.ruby-lang.org/issues/13768
+[Feature #14183]: https://bugs.ruby-lang.org/issues/14183
+[Bug #14266]:     https://bugs.ruby-lang.org/issues/14266
+[Feature #14267]: https://bugs.ruby-lang.org/issues/14267
+[Feature #14413]: https://bugs.ruby-lang.org/issues/14413
+[Bug #14541]:     https://bugs.ruby-lang.org/issues/14541
+[Feature #14722]: https://bugs.ruby-lang.org/issues/14722
+[Bug #15409]:     https://bugs.ruby-lang.org/issues/15409
+[Feature #15504]: https://bugs.ruby-lang.org/issues/15504
+[Feature #15575]: https://bugs.ruby-lang.org/issues/15575
+[Feature #15822]: https://bugs.ruby-lang.org/issues/15822
+[Misc #15893]:    https://bugs.ruby-lang.org/issues/15893
+[Feature #15921]: https://bugs.ruby-lang.org/issues/15921
+[Feature #15973]: https://bugs.ruby-lang.org/issues/15973
+[Feature #16131]: https://bugs.ruby-lang.org/issues/16131
+[Feature #16150]: https://bugs.ruby-lang.org/issues/16150
+[Feature #16166]: https://bugs.ruby-lang.org/issues/16166
+[Feature #16175]: https://bugs.ruby-lang.org/issues/16175
+[Feature #16233]: https://bugs.ruby-lang.org/issues/16233
+[Feature #16260]: https://bugs.ruby-lang.org/issues/16260
+[Feature #16274]: https://bugs.ruby-lang.org/issues/16274
+[Feature #16345]: https://bugs.ruby-lang.org/issues/16345
+[Feature #16377]: https://bugs.ruby-lang.org/issues/16377
+[Feature #16378]: https://bugs.ruby-lang.org/issues/16378
+[Feature #16555]: https://bugs.ruby-lang.org/issues/16555
+[Feature #16604]: https://bugs.ruby-lang.org/issues/16604
+[Feature #16614]: https://bugs.ruby-lang.org/issues/16614
+[Feature #16686]: https://bugs.ruby-lang.org/issues/16686
+[Feature #16746]: https://bugs.ruby-lang.org/issues/16746
+[Feature #16754]: https://bugs.ruby-lang.org/issues/16754
+[Feature #16786]: https://bugs.ruby-lang.org/issues/16786
+[Feature #16792]: https://bugs.ruby-lang.org/issues/16792
+[Feature #16815]: https://bugs.ruby-lang.org/issues/16815
+[Feature #16828]: https://bugs.ruby-lang.org/issues/16828
+[Misc #16961]:    https://bugs.ruby-lang.org/issues/16961
+[Bug #17030]:     https://bugs.ruby-lang.org/issues/17030
+[Feature #17055]: https://bugs.ruby-lang.org/issues/17055
+[Feature #17104]: https://bugs.ruby-lang.org/issues/17104
+[Feature #17122]: https://bugs.ruby-lang.org/issues/17122
+[Feature #17136]: https://bugs.ruby-lang.org/issues/17136
+[Feature #17176]: https://bugs.ruby-lang.org/issues/17176
+[Feature #17187]: https://bugs.ruby-lang.org/issues/17187
+[Bug #17221]:     https://bugs.ruby-lang.org/issues/17221
+[Feature #17260]: https://bugs.ruby-lang.org/issues/17260
+[Feature #17273]: https://bugs.ruby-lang.org/issues/17273
+[Feature #17303]: https://bugs.ruby-lang.org/issues/17303
+[Feature #17314]: https://bugs.ruby-lang.org/issues/17314
+[Feature #17322]: https://bugs.ruby-lang.org/issues/17322
+[Feature #17351]: https://bugs.ruby-lang.org/issues/17351
+[Feature #17371]: https://bugs.ruby-lang.org/issues/17371
+[Bug #17419]:     https://bugs.ruby-lang.org/issues/17419
+[GH-2991]:        https://github.com/ruby/ruby/pull/2991
diff --git a/doc/NEWS/NEWS-3.1.0.md b/doc/NEWS/NEWS-3.1.0.md
new file mode 100644
index 0000000000..fe292fc414
--- /dev/null
+++ b/doc/NEWS/NEWS-3.1.0.md
@@ -0,0 +1,660 @@
+# NEWS for Ruby 3.1.0
+
+This document is a list of user-visible feature changes
+since the **3.0.0** release, except for bug fixes.
+
+Note that each entry is kept to a minimum, see links for details.
+
+## Language changes
+
+*   The block argument can now be anonymous if the block will
+    only be passed to another method. [[Feature #11256]]
+
+    ```ruby
+    def foo(&)
+      bar(&)
+    end
+    ```
+
+*   Pin operator now takes an expression. [[Feature #17411]]
+
+    ```ruby
+    Prime.each_cons(2).lazy.find_all{_1 in [n, ^(n + 2)]}.take(3).to_a
+    #=> [[3, 5], [5, 7], [11, 13]]
+    ```
+
+*   Pin operator now supports instance, class, and global variables.
+    [[Feature #17724]]
+
+    ```ruby
+    @n = 5
+    Prime.each_cons(2).lazy.find{_1 in [n, ^@n]}
+    #=> [3, 5]
+    ```
+
+*   One-line pattern matching is no longer experimental.
+
+*   Parentheses can be omitted in one-line pattern matching.
+    [[Feature #16182]]
+
+    ```ruby
+    [0, 1] => _, x
+    {y: 2} => y:
+    x #=> 1
+    y #=> 2
+    ```
+
+*   Multiple assignment evaluation order has been made consistent with
+    single assignment evaluation order.  With single assignment, Ruby
+    uses a left-to-right evaluation order.  With this code:
+
+    ```ruby
+    foo[0] = bar
+    ```
+
+    The following evaluation order is used:
+
+    1. `foo`
+    2. `bar`
+    3. `[]=` called on the result of `foo`
+
+    In Ruby before 3.1.0, multiple assignment did not follow this
+    evaluation order.  With this code:
+
+    ```ruby
+    foo[0], bar.baz = a, b
+    ```
+
+    Versions of Ruby before 3.1.0 would evaluate in the following
+    order
+
+    1. `a`
+    2. `b`
+    3. `foo`
+    4. `[]=` called on the result of `foo`
+    5. `bar`
+    6. `baz=` called on the result of `bar`
+
+    Starting in Ruby 3.1.0, the evaluation order is now consistent with
+    single assignment, with the left-hand side being evaluated before
+    the right-hand side:
+
+    1. `foo`
+    2. `bar`
+    3. `a`
+    4. `b`
+    5. `[]=` called on the result of `foo`
+    6. `baz=` called on the result of `bar`
+
+    [[Bug #4443]]
+
+*   Values in Hash literals and keyword arguments can be omitted.
+    [[Feature #14579]]
+
+    For example,
+
+    * `{x:, y:}` is a syntax sugar of `{x: x, y: y}`.
+    * `foo(x:, y:)` is a syntax sugar of `foo(x: x, y: y)`.
+
+    Constant names, local variable names, and method names are allowed as
+    key names.  Note that a reserved word is considered as a local
+    variable or method name even if it's a pseudo variable name such as
+    `self`.
+
+*   Non main-Ractors can get instance variables (ivars) of classes/modules
+    if ivars refer to shareable objects.
+    [[Feature #17592]]
+
+*   A command syntax is allowed in endless method definitions, i.e.,
+    you can now write `def foo = puts "Hello"`.
+    Note that `private def foo = puts "Hello"` does not parse.
+    [[Feature #17398]]
+
+## Command line options
+
+* `--disable-gems` is now explicitly declared as "just for debugging".
+  Never use it in any real-world codebase.
+  [[Feature #17684]]
+
+## Core classes updates
+
+Note: We're only listing outstanding class updates.
+
+* Array
+
+    * Array#intersect? is added. [[Feature #15198]]
+
+* Class
+
+    *   Class#subclasses, which returns an array of classes
+        directly inheriting from the receiver, not
+        including singleton classes.
+        [[Feature #18273]]
+
+        ```ruby
+        class A; end
+        class B < A; end
+        class C < B; end
+        class D < A; end
+        A.subclasses    #=> [D, B]
+        B.subclasses    #=> [C]
+        C.subclasses    #=> []
+        ```
+
+* Enumerable
+
+    *   Enumerable#compact is added. [[Feature #17312]]
+
+    *   Enumerable#tally now accepts an optional hash to count. [[Feature #17744]]
+
+    *   Enumerable#each_cons and each_slice to return a receiver. [[GH-1509]]
+
+        ```ruby
+        [1, 2, 3].each_cons(2){}
+        # 3.0 => nil
+        # 3.1 => [1, 2, 3]
+
+        [1, 2, 3].each_slice(2){}
+        # 3.0 => nil
+        # 3.1 => [1, 2, 3]
+        ```
+
+* Enumerator::Lazy
+
+    *   Enumerator::Lazy#compact is added. [[Feature #17312]]
+
+* File
+
+    *   File.dirname now accepts an optional argument for the level to
+        strip path components. [[Feature #12194]]
+
+* GC
+
+    *   "GC.measure_total_time = true" enables the measurement of GC.
+        Measurement can introduce overhead. It is enabled by default.
+        GC.measure_total_time returns the current setting.
+        GC.stat[:time] or GC.stat(:time) returns measured time
+        in milli-seconds. [[[Feature #10917]]]
+
+    *   GC.total_time returns measured time in nano-seconds. [[[Feature #10917]]]
+
+* Integer
+
+    *   Integer.try_convert is added. [[Feature #15211]]
+
+* Kernel
+
+    *   Kernel#load now accepts a module as the second argument,
+        and will load the file using the given module as the
+        top-level module. [[Feature #6210]]
+
+* Marshal
+
+    *   Marshal.load now accepts a `freeze: true` option.
+        All returned objects are frozen except for `Class` and
+        `Module` instances. Strings are deduplicated. [[Feature #18148]]
+
+* MatchData
+
+    *   MatchData#match is added [[Feature #18172]]
+
+    *   MatchData#match_length is added [[Feature #18172]]
+
+* Method / UnboundMethod
+
+    *   Method#public?, Method#private?, Method#protected?,
+        UnboundMethod#public?, UnboundMethod#private?,
+        UnboundMethod#protected? have been added. [[Feature #11689]]
+
+* Module
+
+    *   Module#prepend now modifies the ancestor chain if the receiver
+        already includes the argument. Module#prepend still does not
+        modify the ancestor chain if the receiver has already prepended
+        the argument. [[Bug #17423]]
+
+    *   Module#private, #public, #protected, and #module_function will
+        now return their arguments.  If a single argument is given, it
+        is returned. If no arguments are given, nil is returned.  If
+        multiple arguments are given, they are returned as an array.
+        [[Feature #12495]]
+
+* Process
+
+    *   Process.\_fork is added. This is a core method for fork(2).
+        Do not call this method directly; it is called by existing
+        fork methods: Kernel.#fork, Process.fork, and IO.popen("-").
+        Application monitoring libraries can overwrite this method to
+        hook fork events. [[Feature #17795]]
+
+* Struct
+
+    *   Passing only keyword arguments to Struct#initialize is warned.
+        You need to use a Hash literal to set a Hash to a first member.
+        [[Feature #16806]]
+
+    *   StructClass#keyword_init? is added [[Feature #18008]]
+
+* String
+
+    *   Update Unicode version to 13.0.0 [[Feature #17750]]
+        and Emoji version to 13.0 [[Feature #18029]]
+
+    *   String#unpack and String#unpack1 now accept an `offset:` keyword
+        argument to start the unpacking after an arbitrary number of bytes
+        have been skipped. If `offset` is outside of the string bounds
+        `ArgumentError` is raised. [[Feature #18254]]
+
+* Thread
+
+    *   Thread#native_thread_id is added. [[Feature #17853]]
+
+* Thread::Backtrace
+
+    *   Thread::Backtrace.limit, which returns the value to limit backtrace
+        length set by `--backtrace-limit` command line option, is added.
+        [[Feature #17479]]
+
+* Thread::Queue
+
+    *   Thread::Queue.new now accepts an Enumerable of initial values.
+        [[Feature #17327]]
+
+* Time
+
+    *   Time.new now accepts optional `in:` keyword argument for the
+        timezone, as well as `Time.at` and `Time.now`, so that is now
+        you can omit minor arguments to `Time.new`. [[Feature #17485]]
+
+        ```ruby
+        Time.new(2021, 12, 25, in: "+07:00")
+        #=> 2021-12-25 00:00:00 +0700
+        ```
+
+        At the same time, time component strings are converted to
+        integers more strictly now.
+
+        ```ruby
+        Time.new(2021, 12, 25, "+07:30")
+        #=> invalid value for Integer(): "+07:30" (ArgumentError)
+        ```
+
+        Ruby 3.0 or earlier returned probably unexpected result
+        `2021-12-25 07:00:00`, not `2021-12-25 07:30:00` nor
+        `2021-12-25 00:00:00 +07:30`.
+
+    *   Time#strftime supports RFC 3339 UTC for unknown offset local
+        time, `-0000`, as `%-z`. [[Feature #17544]]
+
+* TracePoint
+
+    *   TracePoint.allow_reentry is added to allow reenter while TracePoint
+        callback.
+        [[Feature #15912]]
+
+* $LOAD_PATH
+
+    *   $LOAD_PATH.resolve_feature_path does not raise. [[Feature #16043]]
+
+* Fiber Scheduler
+
+    *   Add support for `Addrinfo.getaddrinfo` using `address_resolve` hook.
+        [[Feature #17370]]
+
+    *   Introduce non-blocking `Timeout.timeout` using `timeout_after` hook.
+        [[Feature #17470]]
+
+    *   Introduce new scheduler hooks `io_read` and `io_write` along with a
+        low level `IO::Buffer` for zero-copy read/write. [[Feature #18020]]
+
+    *   IO hooks `io_wait`, `io_read`, `io_write`, receive the original IO object
+        where possible. [[Bug #18003]]
+
+    *   Make `Monitor` fiber-safe. [[Bug #17827]]
+
+    *   Replace copy coroutine with pthread implementation. [[Feature #18015]]
+
+* Refinement
+
+    *   New class which represents a module created by Module#refine.
+        `include` and `prepend` are deprecated, and `import_methods` is added
+        instead. [[Bug #17429]]
+
+## Stdlib updates
+
+*   The following default gem are updated.
+    * RubyGems 3.3.3
+    * base64 0.1.1
+    * benchmark 0.2.0
+    * bigdecimal 3.1.1
+    * bundler 2.3.3
+    * cgi 0.3.1
+    * csv 3.2.2
+    * date 3.2.2
+    * did_you_mean 1.6.1
+    * digest 3.1.0
+    * drb 2.1.0
+    * erb 2.2.3
+    * error_highlight 0.3.0
+    * etc 1.3.0
+    * fcntl 1.0.1
+    * fiddle 1.1.0
+    * fileutils 1.6.0
+    * find 0.1.1
+    * io-console 0.5.10
+    * io-wait 0.2.1
+    * ipaddr 1.2.3
+    * irb 1.4.1
+    * json 2.6.1
+    * logger 1.5.0
+    * net-http 0.2.0
+    * net-protocol 0.1.2
+    * nkf 0.1.1
+    * open-uri 0.2.0
+    * openssl 3.0.0
+    * optparse 0.2.0
+    * ostruct 0.5.2
+    * pathname 0.2.0
+    * pp 0.3.0
+    * prettyprint 0.1.1
+    * psych 4.0.3
+    * racc 1.6.0
+    * rdoc 6.4.0
+    * readline 0.0.3
+    * readline-ext 0.1.4
+    * reline 0.3.0
+    * resolv 0.2.1
+    * rinda 0.1.1
+    * ruby2_keywords 0.0.5
+    * securerandom 0.1.1
+    * set 1.0.2
+    * stringio 3.0.1
+    * strscan 3.0.1
+    * tempfile 0.1.2
+    * time 0.2.0
+    * timeout 0.2.0
+    * tmpdir 0.1.2
+    * un 0.2.0
+    * uri 0.11.0
+    * yaml 0.2.0
+    * zlib 2.1.1
+*   The following bundled gems are updated.
+    * minitest 5.15.0
+    * power_assert 2.0.1
+    * rake 13.0.6
+    * test-unit 3.5.3
+    * rexml 3.2.5
+    * rbs 2.0.0
+    * typeprof 0.21.1
+*   The following default gems are now bundled gems.
+    * net-ftp 0.1.3
+    * net-imap 0.2.2
+    * net-pop 0.1.1
+    * net-smtp 0.3.1
+    * matrix 0.4.2
+    * prime 0.1.2
+    * debug 1.4.0
+*   The following gems has been removed from the Ruby standard library.
+    * dbm
+    * gdbm
+    * tracer
+
+* Coverage measurement now supports suspension. You can use `Coverage.suspend`
+  to stop the measurement temporarily, and `Coverage.resume` to restart it.
+  See [[Feature #18176]] in detail.
+
+* Random::Formatter is moved to random/formatter.rb, so that you can
+  use `Random#hex`, `Random#base64`, and so on without SecureRandom.
+  [[Feature #18190]]
+
+## Compatibility issues
+
+Note: Excluding feature bug fixes.
+
+* `rb_io_wait_readable`, `rb_io_wait_writable` and `rb_wait_for_single_fd` are
+  deprecated in favour of `rb_io_maybe_wait_readable`,
+  `rb_io_maybe_wait_writable` and `rb_io_maybe_wait` respectively.
+  `rb_thread_wait_fd` and `rb_thread_fd_writable` are deprecated. [[Bug #18003]]
+
+## Stdlib compatibility issues
+
+* `ERB#initialize` warns `safe_level` and later arguments even without -w.
+  [[Feature #14256]]
+
+* `lib/debug.rb` is replaced with `debug.gem`
+
+* `Kernel#pp` in `lib/pp.rb` uses the width of `IO#winsize` by default.
+  This means that the output width is automatically changed depending on
+  your terminal size. [[Feature #12913]]
+
+* Psych 4.0 changes `Psych.load` as `safe_load` by the default.
+  You may need to use Psych 3.3.2 for migrating to this behavior.
+  [[Bug #17866]]
+
+## C API updates
+
+* Documented. [[GH-4815]]
+
+* `rb_gc_force_recycle` is deprecated and has been changed to a no-op.
+  [[Feature #18290]]
+
+## Implementation improvements
+
+* Inline cache mechanism is introduced for reading class variables.
+  [[Feature #17763]]
+
+* `instance_eval` and `instance_exec` now only allocate a singleton class when
+  required, avoiding extra objects and improving performance. [[GH-5146]]
+
+* The performance of `Struct` accessors is improved. [[GH-5131]]
+
+* `mandatory_only?` builtin special form to improve performance on
+  builtin methods. [[GH-5112]]
+
+* Experimental feature Variable Width Allocation in the garbage collector.
+  This feature is turned off by default and can be enabled by compiling Ruby
+  with flag `USE_RVARGC=1` set. [[Feature #18045]] [[Feature #18239]]
+
+## JIT
+
+* Rename Ruby 3.0's `--jit` to `--mjit`, and alias `--jit` to `--yjit`
+  on non-Windows x86-64 platforms and to `--mjit` on others.
+
+### MJIT
+
+* The default `--mjit-max-cache` is changed from 100 to 10000.
+
+* JIT-ed code is no longer cancelled when a TracePoint for class events
+  is enabled.
+
+* The JIT compiler no longer skips compilation of methods longer than
+  1000 instructions.
+
+* `--mjit-verbose` and `--mjit-warning` output "JIT cancel" when JIT-ed
+  code is disabled because TracePoint or GC.compact is used.
+
+### YJIT: New experimental in-process JIT compiler
+
+New JIT compiler available as an experimental feature. [[Feature #18229]]
+
+See [this blog post](https://shopify.engineering/yjit-just-in-time-compiler-cruby
+) introducing the project.
+
+* Disabled by default, use `--yjit` command-line option to enable YJIT.
+
+* Performance improvements on benchmarks based on real-world software,
+  up to 22% on railsbench, 39% on liquid-render.
+
+* Fast warm-up times.
+
+* Limited to Unix-like x86-64 platforms for now.
+
+## Static analysis
+
+### RBS
+
+*   Generics type parameters can be bounded ([PR](https://github.com/ruby/rbs/pull/844)).
+
+    ```rbs
+    # `T` must be compatible with the `_Output` interface.
+    # `PrettyPrint[String]` is ok, but `PrettyPrint[Integer]` is a type error.
+    class PrettyPrint[T < _Output]
+      interface _Output
+        def <<: (String) -> void
+      end
+
+      attr_reader output: T
+
+      def initialize: (T output) -> void
+    end
+    ```
+
+*   Type aliases can be generic. ([PR](https://github.com/ruby/rbs/pull/823))
+
+    ```rbs
+    # Defines a generic type `list`.
+    type list[T] = [ T, list[T] ]
+                 | nil
+
+    type str_list = list[String]
+    type int_list = list[Integer]
+    ```
+
+* [rbs collection](https://github.com/ruby/rbs/blob/cdd6a3a896001e25bd1feda3eab7f470bae935c1/docs/collection.md) has been introduced to manage gems’ RBSs.
+
+* Many signatures for built-in and standard libraries have been added/updated.
+
+* It includes many bug fixes and performance improvements too.
+
+See the [CHANGELOG.md](https://github.com/ruby/rbs/blob/cdd6a3a896001e25bd1feda3eab7f470bae935c1/CHANGELOG.md) for more information.
+
+### TypeProf
+
+* [Experimental IDE support](https://github.com/ruby/typeprof/blob/ca15c5dae9bd62668463165f8409bd66ce7de223/doc/ide.md) has been implemented.
+* Many bug fixes and performance improvements since Ruby 3.0.0.
+
+## Debugger
+
+* A new debugger [debug.gem](https://github.com/ruby/debug) is bundled.
+  debug.gem is a fast debugger implementation, and it provides many features
+  like remote debugging, colorful REPL, IDE (VSCode) integration, and more.
+  It replaces `lib/debug.rb` standard library.
+
+* `rdbg` command is also installed into `bin/` directory to start and control
+  debugging execution.
+
+## error_highlight
+
+A built-in gem called error_highlight has been introduced.
+It shows fine-grained error locations in the backtrace.
+
+Example: `title = json[:article][:title]`
+
+If `json` is nil, it shows:
+
+```
+$ ruby test.rb
+test.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError)
+
+title = json[:article][:title]
+            ^^^^^^^^^^
+```
+
+If `json[:article]` returns nil, it shows:
+
+```
+$ ruby test.rb
+test.rb:2:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError)
+
+title = json[:article][:title]
+                      ^^^^^^^^
+```
+
+This feature is enabled by default.
+You can disable it by using a command-line option `--disable-error_highlight`.
+See [the repository](https://github.com/ruby/error_highlight) in detail.
+
+## IRB Autocomplete and Document Display
+
+The IRB now has an autocomplete feature, where you can just type in the code, and the completion candidates dialog will appear. You can use Tab and Shift+Tab to move up and down.
+
+If documents are installed when you select a completion candidate, the documentation dialog will appear next to the completion candidates dialog, showing part of the content. You can read the full document by pressing Alt+d.
+
+## Miscellaneous changes
+
+* lib/objspace/trace.rb is added, which is a tool for tracing the object
+  allocation. Just by requiring this file, tracing is started *immediately*.
+  Just by `Kernel#p`, you can investigate where an object was created.
+  Note that just requiring this file brings a large performance overhead.
+  This is only for debugging purposes. Do not use this in production.
+  [[Feature #17762]]
+
+* Now exceptions raised in finalizers will be printed to `STDERR`, unless
+  `$VERBOSE` is `nil`.  [[Feature #17798]]
+
+* `ruby -run -e httpd` displays URLs to access.  [[Feature #17847]]
+
+* Add `ruby -run -e colorize` to colorize Ruby code using
+  `IRB::Color.colorize_code`.
+
+[Bug #4443]:      https://bugs.ruby-lang.org/issues/4443
+[Feature #6210]:  https://bugs.ruby-lang.org/issues/6210
+[Feature #10917]: https://bugs.ruby-lang.org/issues/10917
+[Feature #11256]: https://bugs.ruby-lang.org/issues/11256
+[Feature #11689]: https://bugs.ruby-lang.org/issues/11689
+[Feature #12194]: https://bugs.ruby-lang.org/issues/12194
+[Feature #12495]: https://bugs.ruby-lang.org/issues/12495
+[Feature #12913]: https://bugs.ruby-lang.org/issues/12913
+[Feature #14256]: https://bugs.ruby-lang.org/issues/14256
+[Feature #14579]: https://bugs.ruby-lang.org/issues/14579
+[Feature #15198]: https://bugs.ruby-lang.org/issues/15198
+[Feature #15211]: https://bugs.ruby-lang.org/issues/15211
+[Feature #15912]: https://bugs.ruby-lang.org/issues/15912
+[Feature #16043]: https://bugs.ruby-lang.org/issues/16043
+[Feature #16182]: https://bugs.ruby-lang.org/issues/16182
+[Feature #16806]: https://bugs.ruby-lang.org/issues/16806
+[Feature #17312]: https://bugs.ruby-lang.org/issues/17312
+[Feature #17327]: https://bugs.ruby-lang.org/issues/17327
+[Feature #17370]: https://bugs.ruby-lang.org/issues/17370
+[Feature #17398]: https://bugs.ruby-lang.org/issues/17398
+[Feature #17411]: https://bugs.ruby-lang.org/issues/17411
+[Bug #17423]:     https://bugs.ruby-lang.org/issues/17423
+[Bug #17429]:     https://bugs.ruby-lang.org/issues/17429
+[Feature #17470]: https://bugs.ruby-lang.org/issues/17470
+[Feature #17479]: https://bugs.ruby-lang.org/issues/17479
+[Feature #17485]: https://bugs.ruby-lang.org/issues/17485
+[Feature #17544]: https://bugs.ruby-lang.org/issues/17544
+[Feature #17592]: https://bugs.ruby-lang.org/issues/17592
+[Feature #17684]: https://bugs.ruby-lang.org/issues/17684
+[Feature #17724]: https://bugs.ruby-lang.org/issues/17724
+[Feature #17744]: https://bugs.ruby-lang.org/issues/17744
+[Feature #17750]: https://bugs.ruby-lang.org/issues/17750
+[Feature #17762]: https://bugs.ruby-lang.org/issues/17762
+[Feature #17763]: https://bugs.ruby-lang.org/issues/17763
+[Feature #17795]: https://bugs.ruby-lang.org/issues/17795
+[Feature #17798]: https://bugs.ruby-lang.org/issues/17798
+[Bug #17827]:     https://bugs.ruby-lang.org/issues/17827
+[Feature #17847]: https://bugs.ruby-lang.org/issues/17847
+[Feature #17853]: https://bugs.ruby-lang.org/issues/17853
+[Bug #17866]:     https://bugs.ruby-lang.org/issues/17866
+[Bug #18003]:     https://bugs.ruby-lang.org/issues/18003
+[Feature #18008]: https://bugs.ruby-lang.org/issues/18008
+[Feature #18015]: https://bugs.ruby-lang.org/issues/18015
+[Feature #18020]: https://bugs.ruby-lang.org/issues/18020
+[Feature #18029]: https://bugs.ruby-lang.org/issues/18029
+[Feature #18045]: https://bugs.ruby-lang.org/issues/18045
+[Feature #18148]: https://bugs.ruby-lang.org/issues/18148
+[Feature #18172]: https://bugs.ruby-lang.org/issues/18172
+[Feature #18176]: https://bugs.ruby-lang.org/issues/18176
+[Feature #18190]: https://bugs.ruby-lang.org/issues/18190
+[Feature #18229]: https://bugs.ruby-lang.org/issues/18229
+[Feature #18239]: https://bugs.ruby-lang.org/issues/18239
+[Feature #18254]: https://bugs.ruby-lang.org/issues/18254
+[Feature #18273]: https://bugs.ruby-lang.org/issues/18273
+[Feature #18290]: https://bugs.ruby-lang.org/issues/18290
+
+[GH-1509]: https://github.com/ruby/ruby/pull/1509
+[GH-4815]: https://github.com/ruby/ruby/pull/4815
+[GH-5112]: https://github.com/ruby/ruby/pull/5112
+[GH-5131]: https://github.com/ruby/ruby/pull/5131
+[GH-5146]: https://github.com/ruby/ruby/pull/5146