diff --git a/.jenkins.sh b/.jenkins.sh
index 5b7eb26c66..522e5f4589 100644
--- a/.jenkins.sh
+++ b/.jenkins.sh
@@ -1,3 +1,4 @@
+opam update
 #opam pin add jbuilder https://github.com/janestreet/jbuilder.git
 
 opam pin add --no-action js_of_ocaml .