Crystal 1.21.0 released!

NewsBot · 16 July 2026 18:22

Crystal 1.21.0 has been released.

Breaking changes

stdlib

(runtime) Release: Execution Contexts (#17100, #17104, thanks @ysbaddaden)

(text) Disable automatic fallback to legacy PCRE (#16924, thanks @straight-shoota)

Features

lang

Add %W percent string array literals with interpolation (#16919, thanks @straight-shoota)

(macros) Add TypeNode#all_methods that includes the type’s ancestor’s methods (#16902, thanks @Blacksmoke16)

stdlib

(cli) Align long-only options in OptionParser help ([#16914], thanks @kojix2)

(collection) Make Channel(T) an Iterator(T) ([#16916], thanks @jgaskins)

(crypto) Add support for OpenSSL 4.0 ([#16839], thanks @straight-shoota)

(crypto) Support OpenSSL 4.x DLLs on Windows MSVC ([#17116], thanks @HertzDevil)

(networking) [experimental] Add Socket#sendfile (and Crystal::EventLoop::Socket#sendfile) ([#16665], [#17133], thanks @ysbaddaden, @straight-shoota)

(networking) Add HTTP::WebSocket#receive as a synchronous call ([#16689], thanks @jgaskins)

(runtime) Add Crystal::EventLoop::FileDescriptor#pread ([#17068], thanks @ysbaddaden)

(runtime) Add without_main flag ([#17074], thanks @kojix2)

(runtime) OpenBSD: use kqueue event loop by default ([#17123], thanks @ysbaddaden)

(serialization) Support nested root properties in JSON::Field ([#17016], thanks @tcoatswo)

(serialization) Add URI::Params::Field(ignore:), ignore_serialize, ignore_deserialize ([#17029], thanks @trypsynth)

(specs) Allow chaining #should, #should_not expectations ([#17020], thanks @straight-shoota)

(system) Expose Path#kind ([#1691…

Link: Release 1.21.0 · crystal-lang/crystal · GitHub