diff --git a/build-constraints.yaml b/build-constraints.yaml
index c9b62df0..d996b186 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -2509,7 +2509,7 @@ packages:
         - hw-hspec-hedgehog
         - hw-int
         - hw-fingertree
-        # - hw-fingertree-strict # build failure with ghc 8.4 https://hub.darcs.net/ross/fingertree/issue/5
+        - hw-fingertree-strict
         - hw-json
         - hw-parser
         - hw-prim
@@ -3288,7 +3288,6 @@ packages:
         - heap < 0 # build failure with GHC 8.4 https://github.com/pruvisto/heap/issues/5
         - hpqtypes < 0 # build failure with GHC 8.4 https://github.com/scrive/hpqtypes/issues/7
         - hspec-webdriver < 0 # https://bitbucket.org/wuzzeb/webdriver-utils/issues/9/hspec-webdriver-build-failure-with-ghc-84
-        - hw-fingertree-strict < 0 # build failure with GHC 8.4 https://hub.darcs.net/ross/fingertree/issue/5
         - inline-c < 0 # build failure with GHC 8.4 https://github.com/fpco/inline-c/issues/73
         - 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