# 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 ## Command line options ## Core classes updates Outstanding ones only. * Enumerable * Enumerable#compact is added. [[Feature #17312]] * Enumerator::Lazy * Enumerator::Lazy#compact is added. [[Feature #17312]] * 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]] ## Stdlib updates Outstanding ones only. ## Compatibility issues Excluding feature bug fixes. ## Stdlib compatibility issues ## C API updates ## Implementation improvements ### JIT * `RubyVM::MJIT` is renamed to `RubyVM::JIT`. ## Static analysis ### RBS ### TypeProf ## Miscellaneous changes [Feature #17312]: https://bugs.ruby-lang.org/issues/17312 [Bug #17423]: https://bugs.ruby-lang.org/issues/17423