OCaml 4.11.0, third (and last?) beta release

The release of OCaml 4.11.0 is near.
As one step further in this direction, we have published a third
and potentially last beta release.

This new release fixes an infrequent best-fit allocator bug and an issue
with floating-point software emulation in the ARM EABI port.
On the ecosystem side, merlin is now available for this new version of OCaml.
The compatibility of the opam ecosystem with OCaml 4.11.0 is currently
good, and it should be possible to test this beta without too much trouble.

The source code is available at these addresses:


The compiler can also be installed as an OPAM switch with one of the
following commands:

opam update
opam switch create ocaml-variants.4.11.0+beta3 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git


opam update
opam switch create ocaml-variants.4.11.0+beta3+VARIANT --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git

where you replace VARIANT with one of these: afl, flambda, fp, fp+flambda

We would love to hear about any bugs. Please report them here:

Compared to the previous beta release, the exhaustive list of changes
is as follows:


  • #9736, #9749: Compaction must start in a heap where all free blocks are
    blue, which was not the case with the best-fit allocator.
    (Damien Doligez, report and review by Leo White)
  • [new bug fixes] #9316, #9443, #9463, #9782: Use typing information from Clambda or mutable Cmm variables.
    (Stephen Dolan, review by Vincent Laviron, Guillaume Bury, Xavier Leroy,
    and Gabriel Scherer; temporary bug report by Richard Jones)

Manual and documentation:

  • #9541: Add a documentation page for the instrumented runtime;
    additional changes to option names in the instrumented runtime.
    (Enguerrand Decorne, review by Anil Madhavapeddy, Gabriel Scherer,
    Daniel Bünzli, David Allsopp, Florian Angeletti,
    and Sébastien Hinderer)

Entries marked with “+” were already present in previous alphas, but
they have been complemented by new bug fixes.

If you are interested by the list of new features, and the nearly final list
of bug fixes the updated change log for OCaml 4.11.0 is available at: