diff --git a/build-constraints.yaml b/build-constraints.yaml
index caedd62f..c5870b11 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3293,7 +3293,6 @@ packages:
         - list-t < 0 # build failure with GHC 8.4 # https://github.com/nikita-volkov/list-t/issues/12
         - n-tuple < 0 # build failure with GHC 8.4 https://github.com/athanclark/n-tuple/issues/1
         - pagerduty < 0 # build failure with GHC 8.4 https://github.com/brendanhay/pagerduty/issues/10
-        - pipes-concurrency < 0 # build failure with GHC 8.4 https://github.com/Gabriel439/Haskell-Pipes-Concurrency-Library/issues/47
         - pushbullet-types < 0 # build failure with GHC 8.4 https://github.com/tsani/pushbullet-hs/issues/1
         - rainbow < 0 # build failure with GHC 8.4 https://github.com/massysett/rainbow/issues/6
         - reroute < 0 # build faiulre with GHC 8.4 https://github.com/agrafix/Spock/issues/140
@@ -3542,8 +3541,6 @@ packages:
         - groundhog-mysql < 0 # GHC 8.4 via mysql
         - mysql-simple < 0 # GHC 8.4 via mysql
         - persistent-mysql < 0 # GHC 8.4 via mysql
-        - pipes-fluid < 0 # GHC 8.4 via pipes-concurrency
-        - pipes-misc < 0 # GHC 8.4 via pipes-concurrency
         - pred-trie < 0 # GHC 8.4 via pred-set
         - rainbox < 0 # GHC 8.4 via rainbow
         - reform-blaze < 0 # GHC 8.4 via reform