diff --git a/build-constraints.yaml b/build-constraints.yaml
index 4ba41206..23350abe 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3858,6 +3858,8 @@ packages:
         - wrecker < 0 # GHC 8.4 via tdigest
         - syb-with-class < 0 # GHC 8.4 via template-haskell-2.13.0.0
         - type-assertions < 0 # GHC 8.4 via test-fixture
+        - threepenny-editors < 0 # GHC 8.4
+        - threepenny-gui-flexbox < 0 # GHC 8.4 via clay
         - exception-transformers < 0 # GHC 8.4 via transformers-compat-0.6.0.6
         - monad-control-aligned < 0 # GHC 8.4 via transformers-compat-0.6.0.6