diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+#### 0.2.3.5
+
+* Allow `mtl == 2.2.*`
+
 #### 0.2.3.4
 
 * Widen dependency on aeson-utils to `>= 0.2.1 && < 0.3`
diff --git a/rest-client.cabal b/rest-client.cabal
--- a/rest-client.cabal
+++ b/rest-client.cabal
@@ -1,5 +1,5 @@
 name:                rest-client
-version:             0.2.3.4
+version:             0.2.3.5
 description:         Utility library for use in generated API client libraries.
 synopsis:            Utility library for use in generated API client libraries.
 maintainer:          code@silk.co
@@ -36,7 +36,7 @@
     , hxt >= 9.2 && < 9.4
     , hxt-pickle-utils == 0.1.*
     , monad-control == 0.3.*
-    , mtl >= 2.0 && < 2.2
+    , mtl >= 2.0 && < 2.3
     , resourcet >= 0.4 && < 0.5
     , rest-types == 1.10.*
     , tostring == 0.2.*