diff --git a/glabrous.cabal b/glabrous.cabal
--- a/glabrous.cabal
+++ b/glabrous.cabal
@@ -1,5 +1,5 @@
 name:                glabrous
-version:             0.3.3
+version:             0.3.4
 synopsis:            A template DSL library
 description:         A minimalistic, Mustache-like syntax, truly logic-less,
                      pure Text template DSL library
@@ -30,7 +30,7 @@
                      , bytestring >= 0.10.6 && < 0.11
                      , cereal >= 0.4.1.1 && < 0.6
                      , cereal-text >= 0.1.0 && < 0.2
-                     , either >= 4.4.1 && < 4.6
+                     , either >= 4.4.1 && < 5.1
                      , text >= 1.2.2 && < 1.3
                      , unordered-containers >= 0.2.5.1 && < 0.3
 
@@ -43,7 +43,7 @@
   main-is:             hspec.hs
   build-depends:       base >= 4.8 && < 5
                      , directory > 1.2 && < 1.4
-                     , either >= 4.4.1 && < 4.6
+                     , either >= 4.4.1 && < 5.1
                      , glabrous
                      , hspec >= 2.1.10 && < 2.5
                      , text == 1.2.*