Ruby 2.7

Ruby 2.7 added experimental pattern matching, beginless ranges, numbered block parameters, Enumerable#filter_map and Enumerable#tally, and a compacting garbage collector exposed through GC.compact. It also began the transition to Ruby 3 keyword-argument semantics: calls that rely on implicit conversion between a final positional Hash and keyword arguments can emit warnings because the old behavior is no longer the intended interface. Pattern matching was explicitly experimental, so code using it should not assume its 2.7 behavior is a stable long-term contract.

This cycle has reached end of life, so defects and security issues found in the Ruby runtime will not receive upstream fixes for this line. Staying on it also increases dependency risk as gems, frameworks, and native extensions move their tested and supported Ruby ranges forward. The keyword-argument transition is a particular migration risk: code that appears to work on 2.7 may produce warnings there but fail or behave differently after an upgrade if those warnings are not resolved. Experimental pattern-matching code can require source changes when moving beyond 2.7.

Choose a currently supported Ruby target and run the full application and test suite against it in CI before changing production runtimes. On Ruby 2.7, enable and treat deprecation warnings as migration work, then audit method definitions and call sites that mix positional Hash arguments, keyword arguments, double-splat operators, delegation, and forwarding. Update application dependencies, lockfiles, build images, and native extensions for the selected target, and verify all supported deployment platforms can build and load those extensions. Replace or isolate experimental pattern-matching usage where later Ruby behavior differs, test background jobs and operational scripts as well as the web application, and deploy through a staged rollback-capable release.