diff --git a/build-constraints.yaml b/build-constraints.yaml
index 7252d6f5..d3806a50 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3299,6 +3299,9 @@ packages:
         - brick < 0.21
         - word-wrap < 0.2
 
+        # https://github.com/fpco/stackage/issues/2730
+        - req < 0.4
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of