diff --git a/SimpleForm.hs b/SimpleForm.hs
--- a/SimpleForm.hs
+++ b/SimpleForm.hs
@@ -57,6 +57,7 @@
 ) where
 
 import Data.Maybe
+import Data.Fixed (Fixed, HasResolution)
 import Data.Char (isUpper)
 import Data.Monoid
 import Data.Ratio
@@ -188,6 +189,9 @@
 	wdef = number
 
 instance DefaultWidget Double where
+	wdef = number
+
+instance (HasResolution a) => DefaultWidget (Fixed a) where
 	wdef = number
 
 instance DefaultWidget UTCTime where
diff --git a/SimpleForm/Digestive/Combined.hs b/SimpleForm/Digestive/Combined.hs
--- a/SimpleForm/Digestive/Combined.hs
+++ b/SimpleForm/Digestive/Combined.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 -- | SimpleForm implementation that works along with digestive-functors
 --
 -- The Combined module both renders to 'Html' and also parses input.
@@ -70,8 +71,12 @@
 	-> SimpleForm' m a -- ^ The simple form to render
 	-> m (Html, Maybe a)
 postSimpleForm render env form = do
+#if MIN_VERSION_digestive_functors(0,7,0)
+		(view, val) <- postForm T.empty initialForm (const env)
+#else
 		env' <- env
 		(view, val) <- postForm T.empty initialForm env'
+#endif
 		let html = snd $ simpleForm' render (view, val) form
 		return (html, val)
 	where
diff --git a/SimpleForm/Validation.hs b/SimpleForm/Validation.hs
--- a/SimpleForm/Validation.hs
+++ b/SimpleForm/Validation.hs
@@ -38,6 +38,7 @@
 ) where
 
 import Prelude hiding (read)
+import Data.Fixed (Fixed, HasResolution)
 import Control.Arrow (first, second)
 import Control.Monad
 import Data.Monoid
@@ -116,6 +117,9 @@
 	vdef = read
 
 instance DefaultValidation Double where
+	vdef = read
+
+instance (HasResolution a) => DefaultValidation (Fixed a) where
 	vdef = read
 
 instance DefaultValidation UTCTime where
diff --git a/simple-form.cabal b/simple-form.cabal
--- a/simple-form.cabal
+++ b/simple-form.cabal
@@ -1,5 +1,5 @@
 name:            simple-form
-version:         0.4
+version:         0.4.1
 cabal-version:   >= 1.8
 license:         OtherLicense
 license-file:    COPYING