diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,17 +1,23 @@
 # Revision history for binary-parsec
 
+## 0.2.3.0  -- 2016-09-28
+
+* Remove `MultiWayIf` to support older GHC (7.4 and 7.6).
+* Add `eitherDecoder` and `maybeDecoder`.
+
+
 ## 0.2.2.0  -- 2016-09-21
 
 * Minor optimization to 'takeTill', 'takeWhile' and 'signed'.
 * Add documents on backtracking.
 
-## 0.2.1.0  -- 2016-09-21
+## 0.2.1.0
 
 * Add `parse`,`parseDetail`, `parseDetailLazy`.
 * Reduce these running functions' overhead so that binary performs well on small getters now.
 * Add scanner to benchmarks.
 
-## 0.2.0.0  -- 2016-09-21
+## 0.2.0.0
 
 * Add `endOfLine` combinator.
 * Add http request parsing benchmark.
diff --git a/Data/Binary/Parser.hs b/Data/Binary/Parser.hs
--- a/Data/Binary/Parser.hs
+++ b/Data/Binary/Parser.hs
@@ -76,6 +76,9 @@
     , parseDetail
     , parseDetailLazy
     , parse
+    -- * Decoder conversion
+    , maybeDecoder
+    , eitherDecoder
     -- * Combinators
     , (<?>)
     , endOfInput
@@ -213,6 +216,29 @@
         I.BytesRead n k -> I.BytesRead n (completeLoop . k)
         I.Fail _ _ -> r
         I.Done _ _ -> r
+
+--------------------------------------------------------------------------------
+
+-- | Convert a 'Decoder' value to a 'Maybe' value. A 'Partial' result
+-- is treated as failure.
+--
+-- /Since: 0.2.3.0/
+--
+maybeDecoder :: Decoder r -> Maybe r
+maybeDecoder (Done _ _ r) = Just r
+maybeDecoder _            = Nothing
+{-# INLINE maybeDecoder #-}
+
+-- | Convert a 'Decoder' value to an 'Either' value. A 'Partial'
+-- result is treated as failure.
+--
+-- /Since: 0.2.3.0/
+--
+eitherDecoder :: Decoder r -> Either String r
+eitherDecoder (Done _ _ r)   = Right r
+eitherDecoder (Fail _ _ msg) = Left msg
+eitherDecoder _              = Left "Decoder: incomplete input"
+{-# INLINE eitherDecoder #-}
 
 --------------------------------------------------------------------------------
 
diff --git a/Data/Binary/Parser/Numeric.hs b/Data/Binary/Parser/Numeric.hs
--- a/Data/Binary/Parser/Numeric.hs
+++ b/Data/Binary/Parser/Numeric.hs
@@ -1,5 +1,4 @@
 {-# LANGUAGE CPP          #-}
-{-# LANGUAGE MultiWayIf   #-}
 -- |
 -- Module      :  Data.Binary.Parser.Numeric
 -- Copyright   :  Bryan O'Sullivan 2007-2015, Winterland 2016
@@ -78,9 +77,9 @@
 signed :: Num a => Get a -> Get a
 signed p = do
     w <- W.peek
-    if  | w == MINUS -> W.skipN 1 >> negate <$> p
-        | w == PLUS  -> W.skipN 1 >> p
-        | otherwise  -> p
+    if w == MINUS
+        then W.skipN 1 >> negate <$> p
+        else if w == PLUS then W.skipN 1 >> p else p
 {-# SPECIALISE signed :: Get Int -> Get Int #-}
 {-# SPECIALISE signed :: Get Int8 -> Get Int8 #-}
 {-# SPECIALISE signed :: Get Int16 -> Get Int16 #-}
@@ -153,7 +152,7 @@
     intPart <- decimal
     sci <- (do fracDigits <- W.word8 DOT >> W.takeWhile1 W.isDigit
                let e' = B.length fracDigits
-                   intPart' = intPart * (10 ^ B.length fracDigits)
+                   intPart' = intPart * (10 ^ e')
                    fracPart = LexInt.readDecimal_ fracDigits
                parseE (intPart' + fracPart) e'
            ) <|> (parseE intPart 0)
diff --git a/binary-parsers.cabal b/binary-parsers.cabal
--- a/binary-parsers.cabal
+++ b/binary-parsers.cabal
@@ -1,5 +1,5 @@
 name:                binary-parsers
-version:             0.2.2.0
+version:             0.2.3.0
 synopsis:            Extends binary with parsec/attoparsec style parsing combinators.
 description:         Extends binary with parsec/attoparsec style parsing combinators.
 license:             BSD3