diff --git a/dawg-ord.cabal b/dawg-ord.cabal
--- a/dawg-ord.cabal
+++ b/dawg-ord.cabal
@@ -1,5 +1,5 @@
 name:               dawg-ord
-version:            0.5.1.1
+version:            0.5.1.2
 synopsis:           Directed acyclic word graphs
 description:
     The library implements /directed acyclic word graphs/ (DAWGs) internally
@@ -69,7 +69,7 @@
     build-depends:
         dawg-ord
       , base                    >= 4        && < 5
-      , containers              >= 0.5      && < 0.6
+      , containers              >= 0.5      && < 0.7
       , mtl                     >= 2.1      && < 2.3
       , tasty                   >= 0.10
       , smallcheck              >= 1.1