diff --git a/build-constraints.yaml b/build-constraints.yaml
index 9ad97a5f..f8d5661b 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -657,7 +657,7 @@ packages:
         - derive-storable
 
     "Jeremy Barisch-Rooney <barischj@tcd.ie> @barischrooneyj":
-        - threepenny-gui-flexbox
+        - threepenny-gui-flexbox < 0 # 0.4.2 compile fail https://github.com/jerbaroo/threepenny-gui-flexbox/issues/5
 
     "Romain Edelmann <romain.edelmann@gmail.com> @redelmann":
         - distribution