diff --git a/build-constraints.yaml b/build-constraints.yaml
index 8e8c5b0c..d129f3e5 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3639,13 +3639,14 @@ packages:
         - proto-lens-runtime
         - proto-lens-setup
         - proto-lens
-        - proto-lens-arbitrary
+        # disabled due to QuickCheck < 2.14
+        # - proto-lens-arbitrary
         - proto-lens-optparse
         - tensorflow-test
         - pier-core < 0
         - pier < 0
         - haskeline
-        - ghc-source-gen
+        - ghc-source-gen # tests disabled due to QuickCheck < 2.14
 
     "Christof Schramm <christof.schramm@campus.lmu.de>":
         - mnist-idx
@@ -4996,13 +4997,6 @@ packages:
       # https://github.com/commercialhaskell/stackage/issues/5587
       - network < 3.1.2.0
 
-      # https://github.com/commercialhaskell/stackage/issues/5566
-      # To close this, we may need to set flags.QuickCheck.old-random = true unless we've updated to random 1.2
-      - QuickCheck < 2.14
-      - quickcheck-instances < 0.3.24
-      - splitmix < 0.1
-      - binary-instances < 1.0.1
-
       # https://github.com/commercialhaskell/stackage/issues/5349
       - typed-uuid < 0.1.0.0
 
@@ -5087,6 +5081,8 @@ packages:
 # Package flags are applied to individual packages, and override the values of
 # global-flags
 package-flags:
+    QuickCheck:
+        old-random: true
     pathtype:
         old-time: false
 
@@ -5343,6 +5339,7 @@ skipped-tests:
     - exact-pi # QuickCHeck 2.12, tasty-1.2
     - focuslist # via genvalidity, see https://github.com/commercialhaskell/stackage/pull/4436#issuecomment-475110614
     - ghc-prof # via tasty-1.2
+    - ghc-source-gen # via QuickCheck-2.14
     - github # hspec-2.6.0, hspec-discover-2.6.0
     - hackage-security # QuickCheck
     - haddock-library # base-compat-0.10.1, hspec-2.5.1
@@ -5377,6 +5374,7 @@ skipped-tests:
     - servant-client-core # via hspec-2.7.0
     - servant-docs # via tasty-1.2
     - servant-foreign # via hspec-2.7.0
+    - servant-http-streams # via QuickCheck-2.14
     - servant-js # via hspec-2.7.0
     - servant-server # via hspec-2.7.0
     - servant-swagger # via hspec-2.7.0
@@ -5392,6 +5390,7 @@ skipped-tests:
     - text-short # tasty 1.1
     - these # via tasty-1.2
     - tree-diff # trifecta 2
+    - uniprot-kb # QuickCheck-2.14
     - vector # QuickCheck-2.11.3
     - vinyl # via hspec-2.7.0
     - wide-word # via semirings