diff --git a/Data/Conduit/ImageSize.hs b/Data/Conduit/ImageSize.hs
--- a/Data/Conduit/ImageSize.hs
+++ b/Data/Conduit/ImageSize.hs
@@ -31,7 +31,7 @@
 -- since it looks only at a small part of the header.
 sinkImageInfo :: Monad m => C.Sink S.ByteString m (Maybe (Size, FileFormat))
 sinkImageInfo =
-    C.Processing (pushHeader id) close
+    C.NeedInput (pushHeader id) close
   where
     close = return Nothing
     pushHeader front bs'
@@ -42,7 +42,7 @@
             sinkPush gif $ S.drop 6 bs
         | S.length bs >= 8 && S.take 8 bs == S.pack [137, 80, 78, 71, 13, 10, 26, 10] =
             sinkPush png $ S.drop 8 bs
-        | S.length bs < 11 = C.Processing (pushHeader $ S.append bs) close
+        | S.length bs < 11 = C.NeedInput (pushHeader $ S.append bs) close
         | otherwise = C.Done (Just bs) Nothing
       where
         bs = front bs'
@@ -65,7 +65,7 @@
                 return $ (\w h -> (Size w h, PNG)) <$> mw <*> mh
             else return Nothing
 
-    sinkPush (C.Processing push _) x = push x
+    sinkPush (C.NeedInput push _) x = push x
     sinkPush _ _ = error "Data.Conduit.ImageSize.sinkPush"
 
     jpg = do
diff --git a/imagesize-conduit.cabal b/imagesize-conduit.cabal
--- a/imagesize-conduit.cabal
+++ b/imagesize-conduit.cabal
@@ -1,5 +1,5 @@
 Name:                imagesize-conduit
-Version:             0.3.0
+Version:             0.4.0
 Synopsis:            Determine the size of some common image formats.
 Description:         Currently supports PNG, GIF, and JPEG. This package provides a Sink that will consume the minimum number of bytes necessary to determine the image dimensions.
 License:             BSD3
@@ -18,7 +18,7 @@
 Library
   Exposed-modules:     Data.Conduit.ImageSize
   Build-depends:       base                     >= 4            && < 5
-                     , conduit                  >= 0.3          && < 0.4
+                     , conduit                  >= 0.4          && < 0.5
                      , bytestring               >= 0.9
   ghc-options:     -Wall