diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6722b7c9937282254f3a2dcbc517b6eea810da34..2d251cacde95a3088ce811f8cbb00b2ce5de40d2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -565,6 +565,7 @@ ocaml-versions-nightly:
   image: 'ocaml/opam:ubuntu-20.04-ocaml-$OCAML'
   script:
     - sudo apt update
+    - opam update
     - opam pin . -n -k path
     - opam depext frama-c --with-test
     - opam install --jobs 2 frama-c --with-test --with-doc