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OCaml 4.14.5

This page describes OCaml version 4.14.5, released on Nov 6, 2026. Go here for a list of all releases.

This is a bug-fix and security release of OCaml 4.14.4.

As the last version of OCaml 4, the 4.14 branch receives long-term support during the transition to OCaml 5.

Installation Instructions

The base compiler can be installed as an opam switch with the following commands:

opam update
opam switch create 4.14.5

Configuration Options

The configuration of the installed opam switch can be tuned with the following options:

  • ocaml-option-afl: sets OCaml to be compiled with afl-fuzz instrumentation
  • ocaml-option-bytecode-only: compiles OCaml without the native-code compiler
  • ocaml-option-flambda: sets OCaml to be compiled with flambda activated
  • ocaml-option-musl: sets OCaml to be compiled with musl-gcc
  • ocaml-option-no-flat-float-array: sets OCaml to be compiled with --disable-flat-float-array
  • ocaml-option-static: sets OCaml to be compiled with musl-gcc -static
  • ocaml-option-32bit: sets OCaml to be compiled in 32-bit mode for 64-bit Linux and OS X hosts
  • ocaml-option-nnp: sets OCaml to be compiled with --disable-naked-pointers
  • ocaml-option-nnpchecker: sets OCaml to be compiled with --enable-naked-pointers-checker
  • ocaml-option-fp: sets OCaml to be compiled with frame-pointers enabled

For instance, one can install a switch with both flambda and the naked-pointer checker enabled with:

opam switch create 4.14.5+flambda+nnpchecker ocaml-variants.4.14.5+options ocaml-option-flambda ocaml-option-nnpchecker

Source Distribution

  • Source tarball (.tar.gz) for compilation under Unix (including Linux and macOS X) and Microsoft Windows (including Cygwin).
  • Also available in .zip format.
  • opam is a source-based distribution of OCaml and many companion libraries and tools. Compilation and installation are automated by powerful package managers.
  • The official development repo is hosted on GitHub.

The INSTALL file of the distribution provides detailed compilation and installation instructions. See also the Windows release notes for instructions on how to build under Windows.

Changes for OCaml 4.14.5 (6 November 2026)

Tools

  • #11100: Fix ocamltest to make sure failed tests are not counted as "unexpected error". (Damien Doligez, review by Sébastien Hinderer)

Bug fixes

  • #15019, #15030, OSEC-2026-18: Marshal.from_{string,bytes}: guard against overflow in the computation of the total data length. (Xavier Leroy, report by Akshay Singh, review by Nicolás Ojeda Bär and Antonin Décimo)

  • #15233, OSEC-2026-30: ensure that ephemeron marking follows Infix pointers. (Gabriel Scherer, review by Florian Angeletti)

  • #15185, #15187: fix a pattern-matching miscompilation on certain combinations of immediate ranges and redundant patterns (Gabriel Scherer, report by Alperer Keleş, review by Vincent Laviron and Florian Angeletti)

  • #15067, #15071: Fix detection of functions available in the future on macOS. (Antonin Décimo, review by Nicolás Ojeda Bär and Damien Doligez)

  • #15133, OSEC-2026-24: Multiple issues in command quoting on Windows (Xavier Leroy and Nicolás Ojeda Bär, review by Nicolás Ojeda Bär)

  • #15113, OSEC-2026-21: Str.string_partial_match: make sure captured groups are valid. (Xavier Leroy, review by Nicolás Ojeda Bär and Edwin Török)

  • #15112, OSEC-2026-22: Unix.map_file: protect against overflow when computing the data size. (Xavier Leroy and Nicolás Ojeda Bär, review by Nicolás Ojeda Bär and Edwin Török)

  • #15115, OSEC-2026-23: Fix multiple issues in demarshaling (Marshal.from_{channel,string,bytes}) (Xavier Leroy, review by Nicolás Ojeda Bär)