diff --git a/build-constraints.yaml b/build-constraints.yaml
index f25eb969..828cd687 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -1855,7 +1855,7 @@ packages:
         - panic
         - parameterized-utils
         - s-cargot
-        - what4
+        - what4 < 1.7 # https://github.com/commercialhaskell/stackage/issues/7725
         - zenc
         # copilot tests:
         - hedgehog-classes