diff --git a/happstack-authenticate.cabal b/happstack-authenticate.cabal
--- a/happstack-authenticate.cabal
+++ b/happstack-authenticate.cabal
@@ -1,5 +1,5 @@
 Name:                happstack-authenticate
-Version:             0.9.3
+Version:             0.9.4
 Synopsis:            Happstack Authentication Library
 Description:         A themeable authentication library with support for username+password and OpenId.
 Homepage:            http://src.seereason.com/happstack-authenticate
@@ -30,7 +30,7 @@
                        authenticate                 == 1.2.*,
                        blaze-html                   == 0.5.*,
                        bytestring                   == 0.9.*,
-                       containers                   == 0.4.*,
+                       containers                   >= 0.4 && < 0.6,
                        ixset                        >= 1.0 && < 1.1,
                        happstack-server             >= 6.0 && < 7.1,
                        http-conduit                 == 1.4.*,