# OCaml 5.5.0 — OCaml 5.5.0

- Product: OCaml (https://whatsnew.fyi/product/ocaml)
- Vendor: OCaml
- Date: 2026-06-19
- Version: 5.5.0
- Original notes: https://github.com/ocaml/ocaml/releases/tag/5.5.0
- Permalink: https://whatsnew.fyi/product/ocaml/releases/5.5.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **added** — Module-dependent functions
- **added** — Polymorphic functions as function arguments
- **added** — Relocatable compiler
- **added** — Generalized local definitions
- **added** — Search and replace substring functions
- **added** — External types
- **changed** — Garbage collector improvements
- **added** — Around 60 new functions in the standard library

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