Elixir v1.20.0 is released, requiring Erlang/OTP 27+ and compatible with OTP 29. The headline feature is a major type system overhaul: the type system now understands all language constructs and can infer types for function definitions without requiring explicit type signatures. Key improvements include type inference from guards, whole-body type inference, typing across clauses (occurrence typing for case/cond/with), and full support for non-atom map keys using domain-based typing. Map operations in the Map module are now fully typed, enabling detection of missing or invalid key accesses across module boundaries. Compile-time performance is also improved, with a new :interpreted module_definition option that can significantly speed up compilation on multi-core machines. Additional enhancements span ExUnit, IEx, Mix (dry-run for tests, parallelized dep checks), and the standard library (new Integer functions, SWAR optimizations, etc.). Several hard deprecations are introduced for Logger backends and other APIs.
