diff --git a/src/Text/Foldable.hs b/src/Text/Foldable.hs
--- a/src/Text/Foldable.hs
+++ b/src/Text/Foldable.hs
@@ -69,7 +69,7 @@
 {-| MonoFoldable containing Char -}
 class FoldableString s where
   foldMap :: (Char -> s) -> s -> s
-  default foldMap :: (MonoFoldable s, Element s ~ Char, Monoid m) => (Char -> m) -> s -> m
+  default foldMap :: (MonoFoldable s, Element s ~ Char, Monoid s) => (Char -> s) -> s -> s
   foldMap = ofoldMap
   foldr   :: (Char -> a -> a) -> a -> s -> a
   default foldr :: (MonoFoldable s, Element s ~ Char) => (Char -> a -> a) -> a -> s -> a
diff --git a/string-isos.cabal b/string-isos.cabal
--- a/string-isos.cabal
+++ b/string-isos.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                string-isos
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            Tools for working with isomorphisms of strings
 description:         Haskell has 5 common string types, Text, Lazy Text, ByteString, Lazy ByteString, and String ([Char]). Assuming utf8 encoding, we can make the pain of these conflicts much less via polymorphism.
 license:             BSD3