OCaml

Languages & Runtimes

An industrial-strength functional programming language with an emphasis on expressiveness and safety.

Latest 5.5.0 · by OCamlWebsiteocaml/ocaml

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5
5.5.0
4
4.14.4

Release activity

Release activity — 5 releases across 4 days in the last year. Each cell is one day; darker means more releases that day. Older weeks are hidden at this screen width.
MayJunJulAug
SundayNo releases on May 3, 2026No releases on May 10, 2026No releases on May 17, 2026No releases on May 24, 2026No releases on May 31, 2026No releases on Jun 7, 2026No releases on Jun 14, 2026No releases on Jun 21, 2026No releases on Jun 28, 2026No releases on Jul 5, 2026No releases on Jul 12, 2026No releases on Jul 19, 2026No releases on Jul 26, 2026No releases on Aug 2, 2026No releases on Aug 9, 2026No releases on Aug 16, 2026
MondayNo releases on May 4, 2026No releases on May 11, 2026No releases on May 18, 2026No releases on May 25, 2026No releases on Jun 1, 2026No releases on Jun 8, 20261 release on Jun 15, 2026No releases on Jun 22, 2026No releases on Jun 29, 2026No releases on Jul 6, 2026No releases on Jul 13, 2026No releases on Jul 20, 2026No releases on Jul 27, 2026No releases on Aug 3, 2026No releases on Aug 10, 2026
TuesdayNo releases on May 5, 2026No releases on May 12, 2026No releases on May 19, 2026No releases on May 26, 2026No releases on Jun 2, 2026No releases on Jun 9, 2026No releases on Jun 16, 2026No releases on Jun 23, 2026No releases on Jun 30, 2026No releases on Jul 7, 2026No releases on Jul 14, 2026No releases on Jul 21, 2026No releases on Jul 28, 2026No releases on Aug 4, 2026No releases on Aug 11, 2026
WednesdayNo releases on May 6, 2026No releases on May 13, 2026No releases on May 20, 2026No releases on May 27, 2026No releases on Jun 3, 2026No releases on Jun 10, 2026No releases on Jun 17, 2026No releases on Jun 24, 2026No releases on Jul 1, 2026No releases on Jul 8, 2026No releases on Jul 15, 2026No releases on Jul 22, 2026No releases on Jul 29, 2026No releases on Aug 5, 2026No releases on Aug 12, 2026
ThursdayNo releases on May 7, 2026No releases on May 14, 2026No releases on May 21, 2026No releases on May 28, 2026No releases on Jun 4, 2026No releases on Jun 11, 2026No releases on Jun 18, 2026No releases on Jun 25, 2026No releases on Jul 2, 2026No releases on Jul 9, 2026No releases on Jul 16, 2026No releases on Jul 23, 2026No releases on Jul 30, 2026No releases on Aug 6, 2026No releases on Aug 13, 2026
FridayNo releases on May 8, 2026No releases on May 15, 2026No releases on May 22, 2026No releases on May 29, 2026No releases on Jun 5, 2026No releases on Jun 12, 20261 release on Jun 19, 2026No releases on Jun 26, 2026No releases on Jul 3, 2026No releases on Jul 10, 2026No releases on Jul 17, 2026No releases on Jul 24, 2026No releases on Jul 31, 2026No releases on Aug 7, 2026No releases on Aug 14, 2026
SaturdayNo releases on May 9, 2026No releases on May 16, 2026No releases on May 23, 2026No releases on May 30, 2026No releases on Jun 6, 2026No releases on Jun 13, 2026No releases on Jun 20, 2026No releases on Jun 27, 2026No releases on Jul 4, 2026No releases on Jul 11, 2026No releases on Jul 18, 2026No releases on Jul 25, 2026No releases on Aug 1, 2026No releases on Aug 8, 2026No releases on Aug 15, 2026

5 releases in the last year, busiest day 2

Changelog

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10 of 10 releases
5.5.0Latest

OCaml 5.5.0

Added 7
  • Module-dependent functions
  • Polymorphic functions as function arguments
  • Relocatable compiler
  • Generalized local definitions
  • Search and replace substring functions
  • External types
  • Around 60 new functions in the standard library
Changed 1
  • Garbage collector improvements

Some of the highlights of OCaml 5.5.0 are:

  • Module-dependent functions
  • Polymorphic functions as function arguments
  • Relocatable compiler
  • Generalized local definitions
  • Search and replace substring functions
  • External types
  • Garbage collector improvements
  • Around 60 new functions in the standard library
View originalPermalink
How 5.5.0 went
4.14.4

OCaml 4.14.4

Fixed 1
  • Bug fixes for 4.14.3
Security 2
  • Fix size overflow check in caml_ba_reshape (CVE-2026-34353, OSEC-2026-04)
  • Fix quoting of filenames passed to Filename.quote_command on Windows
  • Security fix for check for size overflow in caml_ba_reshape (CVE-2026-34353, OSEC-2026-04)
  • Security fix for quoting of filenames passed to Filename.quote_command on Windows
  • Bug fixes for 4.14.3

See detailed list of changes.

View originalPermalink
How 4.14.4 went
5.4.0

OCaml 5.4.0

Added 7
  • Labelled tuples
  • Immutable arrays
  • Array literal syntax support for immutable arrays and floatarrays through type-directed disambiguation
  • Atomic record fields
  • Four new standard library modules: Pair, Pqueue, Repr, and Iarray
  • More than thirty new standard library functions
  • New chapter in the manual on profiling OCaml programs on Linux and macOS
Changed 3
  • Restored memory cleanup upon exit mode
  • Many runtime and code generation improvements
  • Nearly a dozen improved error messages
Fixed 1
  • Around fifty bug fixes

Some of the highlights of OCaml 5.4.0 are:

  • Labelled tuples
  • Immutable arrays
  • Array literal syntax support for immutable arrays and floatarrays (through type-directed disambiguation)
  • Atomic record fields
  • Four new standard library modules: Pair, Pqueue, Repr, and Iarray
  • Restored "memory cleanup upon exit" mode
  • New chapter in the manual on profiling OCaml programs on Linux and macOS

And a lot of incremental changes:

  • Many runtime and code generation improvements
  • More than thirty new standard library functions
  • Nearly a dozen improved error messages
  • Around fifty bug fixes
View originalPermalink
How 5.4.0 went
5.3.0

OCaml 5.3.0

Added 4
  • Syntax for deep effect handlers
  • Statistical memory profiling (statmemprof)
  • UTF-8 encoded Unicode source files and support for Unicode identifiers
  • Around 20 new functions in the standard library
Changed 3
  • More space-efficient implementation of Dynarray
  • Improved metadata on pairs of declarations and definitions for merlin
  • Improved error messages for first-class modules, functors, labeled arguments, and type clashes
Fixed 3
  • Restored MSVC port
  • Many fixes and improvements in the runtime
  • Numerous bug fixes

Some of the highlights in OCaml 5.3.0 are:

  • Syntax for deep effect handlers
  • Restored MSVC port
  • Re-introduced statistical memory profiling (statmemprof)
  • utf-8 encoded Unicode source files and modest support of Unicode identifiers
  • More space-efficient implementation of Dynarray
  • Improved metadata on the pairs of declarations and definitions for merlin.

And a lot of incremental changes:

  • Around 20 new functions in the standard library
  • Many fixes and improvements in the runtime
  • Improved error messages for first-class modules, functors, labeled arguments, type clashes.
  • Numerous bug fixes
View originalPermalink
How 5.3.0 went
5.2.0

OCaml 5.2.0

Added 9
  • Re-introduced GC compaction
  • Restored native backend for POWER 64 bits
  • Thread sanitizer support
  • New Dynarray module
  • New -H flag for hidden include directories
  • Project-wide occurence metadata support for developer tools
Changed 1
  • Many fixes and improvements in the runtime
Fixed 1
  • Many bug fixes

OCaml 5.2.0 is still a somewhat experimental release compared to the OCaml 4.14 branch. Some of the highlights in OCaml 5.2.0 are:

  • Re-introduced GC compaction
  • Restored native backend for POWER 64 bits
  • Thread sanitizer support
  • New Dynarray module
  • New -H flag for hidden include directories
  • Project-wide occurence metadata support for developer tools
  • Raw identifiers
  • Local open in type expressions

And a lot of incremental changes:

  • Around 20 new functions in the standard library
  • Many fixes and improvements in the runtime
  • Many bug fixes
View originalPermalink
How 5.2.0 went
5.1.1

OCaml 5.1.1

Removed 1
  • Remove Marshal.Compression module, compressed marshaling has been moved to an internal compiler library
  • Breaking change: Marshal.Compression has been removed, compressed marshaling has been moved to an internal compiler library
  • Bug fixes. See detailed list of changes.
View originalPermalink
How 5.1.1 went

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