diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 507f437635cf0462f57c2926191912843ae05b67..7dce153959f65db1a3ed9162f19597a6c9391673 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -33,6 +33,7 @@ build-coq.8.15.1:
   variables:
     OPAM_PINS: "coq version 8.15.1"
     DENY_WARNINGS: "1"
+    OPAM_PKG: "1"
 
 trigger-iris.dev:
   <<: *template