diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 88e2d8a6..e2ceb80c 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -40,5 +40,7 @@ jobs:
 
       # install some depopts
       - run: opam install thread-local-storage trace domain-local-await
+        if: matrix.ocaml-compiler == '5.1'
+
       - run: opam exec -- dune build @install @runtest