diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5d2e8af1b96875c4a9f2272edef2cfd686ad7bcb..a2039cc4c60b0523be6caa5486a999bc6b17b813 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: