diff --git a/build-constraints.yaml b/build-constraints.yaml
index e3c31dde..54328412 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4411,7 +4411,7 @@ packages:
         # th-desugar < 1.9
 
         # https://github.com/commercialhaskell/stackage/issues/3990
-        # stm < 2.5
+        - stm < 2.5
 
         # https://github.com/commercialhaskell/stackage/issues/4001
         # http-api-data < 0.3.9