diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+#### 0.2.1.1
+
+* Allow utf8-string 1.
+
 ### 0.2.1
 
 * Add `ToString` instance for `case-insensitive`.
diff --git a/tostring.cabal b/tostring.cabal
--- a/tostring.cabal
+++ b/tostring.cabal
@@ -1,5 +1,5 @@
 name:                tostring
-version:             0.2.1
+version:             0.2.1.1
 synopsis:            The ToString class
 description:         A type class for converting text types to String.
 license:             BSD3
@@ -27,4 +27,4 @@
       base == 4.*
     , case-insensitive >= 1.0 && < 1.3
     , text >= 0.11 && < 1.3
-    , utf8-string == 0.3.*
+    , utf8-string >= 0.3 && < 1.1