diff --git a/hint-server.cabal b/hint-server.cabal
--- a/hint-server.cabal
+++ b/hint-server.cabal
@@ -1,5 +1,5 @@
 name: hint-server
-version: 1.2.0
+version: 1.2.1
 cabal-version: >=1.6
 build-type: Simple
 license: BSD3
@@ -25,7 +25,7 @@
 
 Library
     build-depends: base >= 4,                   base < 5,
-                   mtl >=1.1.0,                 mtl < 1.2,
+                   mtl >=1.1.0,                 mtl < 2.1,
                    monad-loops >=0.3.0,         monad-loops < 0.4,
                    hint >=0.3.1,                hint < 0.4,
                    eprocess >=1.1.2,            eprocess < 2