diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+1.5.12
+
+* Increase upper bound on `containers`
+
 1.5.11
 
 * Don't forward broken pipe exceptions when using `inproc`
diff --git a/turtle.cabal b/turtle.cabal
--- a/turtle.cabal
+++ b/turtle.cabal
@@ -1,5 +1,5 @@
 Name: turtle
-Version: 1.5.11
+Version: 1.5.12
 Cabal-Version: >=1.10
 Build-Type: Simple
 License: BSD3
@@ -54,7 +54,7 @@
         async                >= 2.0.0.0 && < 2.3 ,
         bytestring           >= 0.9.1.8 && < 0.11,
         clock                >= 0.4.1.2 && < 0.8 ,
-        containers           >= 0.5.0.0 && < 0.6 ,
+        containers           >= 0.5.0.0 && < 0.7 ,
         directory            >= 1.0.7   && < 1.4 ,
         exceptions           >= 0.4     && < 0.11,
         foldl                >= 1.1     && < 1.5 ,