https://adtmag.com/articles/2025/04/23/jruby-10-released.aspx

The JRuby team has released JRuby 10, a major upgrade of the Ruby implementation on the Java Virtual Machine (JVM), introducing compatibility with Ruby 3.4, full support for Java 21, and several performance and startup-time improvements enabled by recent developments in the Java platform.

JRuby 10 is the project’s first major version update since JRuby 9.4, released over three years ago. With this release, JRuby now incorporates features from Ruby 3.2, 3.3, and 3.4, and has passed thousands of new tests and specifications. The release also marks the end of support for Java 8, which had been maintained for over a decade.