Official post
- YJIT: New experimental in-process JIT compiler disabled by default (needs --yjit cli option), limited to Unix-like x86-64 platforms for now
- debug gem: A new debugger
- error_highlight: Fine-grained error location in backtrace
- IRB Autocomplete and Document Display
- Values in Hash literals and keyword arguments can be omitted
- Pin operator in pattern matching now takes an expression