diff --git a/build-constraints.yaml b/build-constraints.yaml
index 9c5c2591..0ab5775f 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -709,8 +709,7 @@ packages:
     "Stackage upper bounds":
 
         # Force a specific version that's compatible with transformers 0.3
-        - transformers-compat == 0.3.3.3
-        - mtl-compat < 0.2 # https://github.com/fpco/stackage/issues/446
+        - transformers-compat == 0.4.0.3
 
         # https://github.com/fpco/stackage/issues/291
         - random < 1.0.1.3