diff --git a/build-constraints.yaml b/build-constraints.yaml
index 54174507..8e90f1af 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3046,8 +3046,6 @@ packages:
         # https://github.com/fpco/stackage/issues/2400
         - hslua < 0.5
 
-        # https://github.com/fpco/stackage/issues/2421
-        - IPv6Addr < 1.0.0
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of