Index: b/quickcheck-classes-base.cabal
===================================================================
--- a/quickcheck-classes-base.cabal
+++ b/quickcheck-classes-base.cabal
@@ -1,6 +1,7 @@
 cabal-version: 2.4
 name: quickcheck-classes-base
 version: 0.6.2.0
+x-revision: 1
 synopsis: QuickCheck common typeclasses from `base`
 description:
   This libary is a minimal variant of `quickcheck-classes` that
@@ -82,7 +83,7 @@ library
   build-depends:
     , base >= 4.5 && < 5
     , QuickCheck >= 2.7
-    , transformers >= 0.3 && < 0.6
+    , transformers >= 0.3 && < 0.7
     , containers >= 0.4.2.1
   if impl(ghc < 8.6)
     build-depends: contravariant
