diff --git a/build-constraints.yaml b/build-constraints.yaml
index beb8d03e..f65b47c4 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3995,11 +3995,11 @@ packages:
         - map-syntax < 0 # GHC 8.4 via base-4.11.0.0
         - heist < 0 # GHC 8.4 via map-syntax
         - snap < 0 # GHC 8.4 via base-4.11.0.0
-        - conferer
+        - conferer < 1.1 # https://github.com/commercialhaskell/stackage/issues/5896
         #- conferer-snap # Because snap
         - conferer-warp
         - conferer-hspec
-        - conferer-aeson
+        - conferer-aeson < 1.1 # https://github.com/commercialhaskell/stackage/issues/5896
 
     "Tim Humphries <tim+stackage@utf8.me> @thumphries":
         - transformers-either < 0 # via exceptions-0.10.0