# Ocaml version 5.5 not compiling on the codecrafters test engine

**URL:** <https://forum.codecrafters.io/t/ocaml-version-5-5-not-compiling-on-the-codecrafters-test-engine/16241>\
**Category:** Bug Reports\
**Tags:** challenge:http-server\
**Created:** [August 20, 2026, 5:44am UTC](https://forum.codecrafters.io/t/ocaml-version-5-5-not-compiling-on-the-codecrafters-test-engine/16241 "2026-08-20T05:44:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![gitting-gud11](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/gitting-gud11/32/27134_2.png) [@gitting-gud11](https://forum.codecrafters.io/u/gitting-gud11)\
**Post date:** [August 20, 2026, 5:44am UTC](https://forum.codecrafters.io/t/ocaml-version-5-5-not-compiling-on-the-codecrafters-test-engine/16241/1 "2026-08-20T05:44:00Z")

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I am working on the HTTP server challenge in OCaml; however, it does not appear that version 5.4, the most recent one is supported on the test engine. My code works locally; however, it does not compile when testing citing that `String.split_all` is unbound.

 ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/5/9/5946986533b4ff9964106403ee5f1f28d7ae9cbf.png)

 ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/b/d/bd42b71f587b28253180595fbe6a3bae74c72aa1.png)

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**Author:** ![yeswanth](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/yeswanth/32/27558_2.png) [@yeswanth](https://forum.codecrafters.io/u/yeswanth)\
**Post date:** [August 27, 2026, 3:41pm UTC](https://forum.codecrafters.io/t/ocaml-version-5-5-not-compiling-on-the-codecrafters-test-engine/16241/3 "2026-08-27T15:41:26Z")

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Thank you for reporting it. I’ve updated OCaml to v5.5 for the HTTP server challenge.