diff --git a/build-constraints.yaml b/build-constraints.yaml
index ade038c0..f7496850 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -722,6 +722,9 @@ packages:
         # https://github.com/fpco/stackage/issues/424
         - control-monad-free < 0.6
 
+        # https://github.com/fpco/stackage/issues/426
+        - utf8-string < 1
+
 # Package flags are applied to individual packages, and override the values of
 # global-flags
 package-flags: