diff --git a/Network/URL.hs b/Network/URL.hs
--- a/Network/URL.hs
+++ b/Network/URL.hs
@@ -238,9 +238,9 @@
 ok_path c   = ok_param c || c `elem` "/=&"
 
 -- XXX: others? check RFC
--- | Characters that may appear in the textual representation of a URL
+-- | Characters that do not need to be encoded in URL
 ok_url :: Char -> Bool
-ok_url c = isDigit c || isAlphaASCII c || c `elem` ".-;:@$_!*'(),/=&?~%+"
+ok_url c = isDigit c || isAlphaASCII c || c `elem` ".-;:@$_!*'(),/=&?~+"
 
 -- Misc
 --------------------------------------------------------------------------------
diff --git a/url.cabal b/url.cabal
--- a/url.cabal
+++ b/url.cabal
@@ -1,5 +1,5 @@
 name:         url
-version:      2.1.2
+version:      2.1.3
 category:     Web
 synopsis:     A library for working with URLs.
 description:  A library for working with URLs.