OCaml Platform Newsletter: September to October 2025

OCaml 5.4.0 has been released with major language enhancements including labelled tuples, immutable arrays, unified array literal syntax, and atomic record fields. The release also adds four new standard library modules and runtime improvements for ARM64 and other architectures. A new Security Response Team has been established to handle vulnerabilities in the OCaml ecosystem. Editor support improved with OCaml-LSP 1.24.0 and Merlin 5.6 releases. OCaml.org now separates stable releases (OCaml Changelog) from experimental work (Backstage OCaml). Experimental tools include Gospel ecosystem for specification-driven testing, ocaml.nvim plugin for Neovim, and Dune package management features. Work continues on Relocatable OCaml targeting OCaml 5.5.