Clojure
Clojure 1.13.0-alpha9

Clojure 1.13.0-alpha9

09 October 2026
Alex Miller

Clojure 1.13.0-alpha9 is now available! Find download and usage information on the Downloads page.

  • Dropped :defaults directive - use cases better handled by others now

  • CLJ-2983 Removed :defaults tests

  • Faster transient propagation of metadata in into and update-vals

  • Revise impl and inline of meta? via RT

  • CLJ-2978 Catch protocol extension of non-protocol methods

  • CLJ-2982 TransientArrayMap should expand to same threshold as PersistentArrayMap

  • Favor class files when reproducible build sets class and source timestamps the same

  • CLJ-2984 Set file timestamps to last git commit time

Try it out

Update your deps.edn :deps with:

org.clojure/clojure {:mvn/version "1.13.0-alpha9"}

Start a REPL with the Clojure CLI (any version) with:

clj -Sdeps '{:deps {org.clojure/clojure {:mvn/version "1.13.0-alpha9"}}}'