diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index bca215d77c5ddc852ee346349d530d1c28954aeb..b2ac15627255b64897022dc0279eb14853e7a912 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -5,7 +5,7 @@ stages:
 
 variables:
   CPU_CORES: "10"
-  OCAML: "ocaml-base-compiler.4.13.2"
+  OCAML: "ocaml-base-compiler.4.13.1"
 
 .only_branches: &only_branches
   only: