diff --git a/references.cabal b/references.cabal
--- a/references.cabal
+++ b/references.cabal
@@ -1,5 +1,5 @@
 name:                references
-version:             0.3.3.0
+version:             0.3.3.1
 synopsis:            Selectors for reading and updating data.
 
 description:         References are data accessors that can read, write or update the accessed infromation through their context. They are first-class values, can be passed in functions, transformed, combined. References generalize lenses, folds and traversals for haskell (see: < https://hackage.haskell.org/package/lens>).
@@ -114,7 +114,7 @@
                      , mtl                  >= 2.2 && < 3
                      , transformers         >= 0.4 && < 1
                      , containers           >= 0.5 && < 1
-                     , either               >= 4.3 && < 5
+                     , either               >= 4.3 && < 6
                      , template-haskell     >= 2.8 && < 3
                      , instance-control     >= 0.1 && < 1
                      , directory            >= 1.2 && < 2