diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 3.2.1.1
+
+* Relax upper bound on bytestring-builder
+
 ## 3.2.1
 
 * add mapResponseStatus [#532](https://github.com/yesodweb/wai/pull/532)
diff --git a/wai.cabal b/wai.cabal
--- a/wai.cabal
+++ b/wai.cabal
@@ -1,5 +1,5 @@
 Name:                wai
-Version:             3.2.1
+Version:             3.2.1.1
 Synopsis:            Web Application Interface.
 Description:         Provides a common protocol for communication between web applications and web servers.
 description:         API docs and the README are available at <http://www.stackage.org/package/wai>.
@@ -21,7 +21,7 @@
 Library
   Build-Depends:     base                      >= 4        && < 5
                    , bytestring                >= 0.10
-                   , bytestring-builder        >= 0.10.4.0 && < 0.10.7
+                   , bytestring-builder        >= 0.10.4.0 && < 0.11
                    , blaze-builder             >= 0.2.1.4  && < 0.5
                    , network                   >= 2.2.1.5
                    , http-types                >= 0.7