OCaml 4.10.0 (Feb 21, 2020)

• New best-fit allocator for the major heap
• Preliminary runtime work for OCaml multicore
• Immutable strings are now enforced at configuration time
• User-defined indexing operators for multidimensional arrays
• Coming soon: statmemprof, a new statistical memory profiler.
• The external API will be released next version.
• Various improvements to the manual
• More precise exhaustiveness check for GADTs
• Many bug fixes

OCaml 4.09.0 (Sep 18, 2019)

• New optimisations, in particular for affine functions in matches.
• The graphics library was moved out of the compiler distribution.
• The vmthread library was removed.
• Support for compiler plugins was removed.
• Many bug fixes.