diff --git a/amazonka-core.cabal b/amazonka-core.cabal
--- a/amazonka-core.cabal
+++ b/amazonka-core.cabal
@@ -1,5 +1,5 @@
 name:                  amazonka-core
-version:               0.3.2
+version:               0.3.3
 synopsis:              Core functionality and data types for Amazonka libraries.
 homepage:              https://github.com/brendanhay/amazonka
 license:               OtherLicense
@@ -93,13 +93,14 @@
         , http-types           >= 0.8
         , lens                 >= 4.4     && < 5
         , mmorph               >= 1       && < 2
-        , mtl                  >= 2.2.1   && < 2.3
+        , mtl                  >= 2.1.3.1
         , resourcet            == 1.1.*
         , scientific           == 0.3.*
         , semigroups           >= 0.12
         , tagged               >= 0.7
         , text                 >= 1.1
-        , transformers         == 0.4.*
+        , transformers         >= 0.2
+        , transformers-compat  >= 0.3
         , unordered-containers >= 0.2.5
         , vector               >= 0.10.9
         , xml-conduit          == 1.2.*