diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,4 +1,8 @@
 # pseudo-boolean
 Haskell library for parsing/generating OPB/WBO files used in pseudo boolean competition.
 
-[![Build Status](https://secure.travis-ci.org/msakai/pseudo-boolean.png?branch=master)](http://travis-ci.org/msakai/pseudo-boolean) [![Coverage Status](https://coveralls.io/repos/msakai/pseudo-boolean/badge.svg)](https://coveralls.io/r/msakai/pseudo-boolean) [![Hackage](https://budueba.com/hackage/pseudo-boolean)](https://hackage.haskell.org/package/pseudo-boolean)
+[![Build Status](https://travis-ci.org/msakai/pseudo-boolean.svg?branch=master)](https://travis-ci.org/msakai/pseudo-boolean)
+[![Coverage Status](https://coveralls.io/repos/msakai/pseudo-boolean/badge.svg)](https://coveralls.io/r/msakai/pseudo-boolean)
+[![Hackage](https://img.shields.io/hackage/v/pseudo-boolean.svg)](https://hackage.haskell.org/package/pseudo-boolean)
+[![Hackage Deps](https://img.shields.io/hackage-deps/v/pseudo-boolean.svg)](https://packdeps.haskellers.com/feed?needle=pseudo-boolean)
+[![License](https://img.shields.io/badge/License-BSD%203--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause)
diff --git a/pseudo-boolean.cabal b/pseudo-boolean.cabal
--- a/pseudo-boolean.cabal
+++ b/pseudo-boolean.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                pseudo-boolean
-version:             0.1.6.0
+version:             0.1.7.0
 synopsis:            Reading/Writing OPB/WBO files used in pseudo boolean competition
 description:         Reading\/Writing OPB\/WBO files used in pseudo boolean competition
 homepage:            https://github.com/msakai/pseudo-boolean
@@ -21,6 +21,12 @@
     test/samples/normalized-1096.cudf.paranoid.opb
     test/samples/*.wbo
 cabal-version:       >=1.10
+tested-with:
+   GHC ==7.8.4
+   GHC ==7.10.3
+   GHC ==8.0.2
+   GHC ==8.2.2
+   GHC ==8.4.3
 
 source-repository head
   type:     git
@@ -46,10 +52,10 @@
      FlexibleContexts
      OverloadedStrings
   build-depends:
-     base >=4.6.0.1 && <4.11,
+     base >=4.6.0.1 && <4.13,
      containers >=0.4.2.1,
      parsec >=3.1.2 && <4,
-     megaparsec >=4 && <7,
+     megaparsec >=4 && <8,
      bytestring >=0.9.2.1 && <0.11,
      bytestring-builder,
      dlist >=0.7.0 && <0.9.0,
@@ -69,8 +75,8 @@
     base,
     bytestring,
     tasty >=0.10.1,
-    tasty-hunit ==0.9.*,
-    tasty-quickcheck >=0.8 && <0.10,
+    tasty-hunit >=0.9 && <0.11,
+    tasty-quickcheck >=0.8 && <0.11,
     tasty-th,
     HUnit,
     QuickCheck >=2.5 && <3,
diff --git a/src/Data/PseudoBoolean/Megaparsec.hs b/src/Data/PseudoBoolean/Megaparsec.hs
--- a/src/Data/PseudoBoolean/Megaparsec.hs
+++ b/src/Data/PseudoBoolean/Megaparsec.hs
@@ -33,6 +33,9 @@
   , parseWBOString
   , parseWBOByteString
   , parseWBOFile
+
+  -- * Error type
+  , ParseError
   ) where
 
 import Prelude hiding (sum)
@@ -46,7 +49,8 @@
 import Data.Word
 import Data.Void
 #endif
-import Text.Megaparsec
+import Text.Megaparsec hiding (ParseError)
+import qualified Text.Megaparsec as MP
 #if MIN_VERSION_megaparsec(6,0,0)
 import Text.Megaparsec.Byte
 #else
@@ -75,6 +79,11 @@
 
 #endif
 
+#if MIN_VERSION_megaparsec(7,0,0)
+anyChar :: C e s m => m Word8
+anyChar = anySingle
+#endif
+
 -- | Parser for OPB files
 #if MIN_VERSION_megaparsec(6,0,0)
 opbParser :: (MonadParsec e s m, Token s ~ Word8, IsString (Tokens s)) => m Formula
@@ -246,37 +255,30 @@
 literal :: C e s m => m Lit
 literal = variablename <|> (char8 '~' >> liftM negate variablename)
 
+#if MIN_VERSION_megaparsec(7,0,0)
+type ParseError = MP.ParseErrorBundle BL.ByteString Void
+#elif MIN_VERSION_megaparsec(6,0,0)
+type ParseError = MP.ParseError Word8 Void
+#elif MIN_VERSION_megaparsec(5,0,0)
+type ParseError = MP.ParseError Char Dec
+#else
+type ParseError = MP.ParseError
+#endif
+
 -- | Parse a OPB format string containing pseudo boolean problem.
+parseOPBString :: String -> String -> Either ParseError Formula
 #if MIN_VERSION_megaparsec(6,0,0)
-parseOPBString :: String -> String -> Either (ParseError Word8 Void) Formula
 parseOPBString info s = parse (formula <* eof) info (BL.pack s)
 #else
-#if MIN_VERSION_megaparsec(5,0,0)
-parseOPBString :: String -> String -> Either (ParseError Char Dec) Formula
-#else
-parseOPBString :: String -> String -> Either ParseError Formula
-#endif
 parseOPBString = parse (formula <* eof)
 #endif
 
 -- | Parse a OPB format lazy bytestring containing pseudo boolean problem.
-#if MIN_VERSION_megaparsec(6,0,0)
-parseOPBByteString :: String -> ByteString -> Either (ParseError Word8 Void) Formula
-#elif MIN_VERSION_megaparsec(5,0,0)
-parseOPBByteString :: String -> ByteString -> Either (ParseError Char Dec) Formula
-#else
 parseOPBByteString :: String -> ByteString -> Either ParseError Formula
-#endif
 parseOPBByteString = parse (formula <* eof)
 
 -- | Parse a OPB file containing pseudo boolean problem.
-#if MIN_VERSION_megaparsec(6,0,0)
-parseOPBFile :: FilePath -> IO (Either (ParseError Word8 Void) Formula)
-#elif MIN_VERSION_megaparsec(5,0,0)
-parseOPBFile :: FilePath -> IO (Either (ParseError Char Dec) Formula)
-#else
 parseOPBFile :: FilePath -> IO (Either ParseError Formula)
-#endif
 parseOPBFile filepath = do
   s <- BL.readFile filepath
   return $! parse (formula <* eof) filepath s
@@ -331,36 +333,19 @@
   return (Just cost, c)
 
 -- | Parse a WBO format string containing weighted boolean optimization problem.
+parseWBOString :: String -> String -> Either ParseError SoftFormula
 #if MIN_VERSION_megaparsec(6,0,0)
-parseWBOString :: String -> String -> Either (ParseError Word8 Void) SoftFormula
 parseWBOString info s = parse (softformula <* eof) info (BL.pack s)
 #else
-#if MIN_VERSION_megaparsec(5,0,0)
-parseWBOString :: String -> String -> Either (ParseError Char Dec) SoftFormula
-#else
-parseWBOString :: String -> String -> Either ParseError SoftFormula
-#endif
 parseWBOString = parse (softformula <* eof)
 #endif
 
 -- | Parse a WBO format lazy bytestring containing pseudo boolean problem.
-#if MIN_VERSION_megaparsec(6,0,0)
-parseWBOByteString :: String -> ByteString -> Either (ParseError Word8 Void) SoftFormula
-#elif MIN_VERSION_megaparsec(5,0,0)
-parseWBOByteString :: String -> ByteString -> Either (ParseError Char Dec) SoftFormula
-#else
 parseWBOByteString :: String -> ByteString -> Either ParseError SoftFormula
-#endif
 parseWBOByteString = parse (softformula <* eof)
 
 -- | Parse a WBO file containing weighted boolean optimization problem.
-#if MIN_VERSION_megaparsec(6,0,0)
-parseWBOFile :: FilePath -> IO (Either (ParseError Word8 Void) SoftFormula)
-#elif MIN_VERSION_megaparsec(5,0,0)
-parseWBOFile :: FilePath -> IO (Either (ParseError Char Dec) SoftFormula)
-#else
 parseWBOFile :: FilePath -> IO (Either ParseError SoftFormula)
-#endif
 parseWBOFile filepath = do
   s <- BL.readFile filepath
   return $! parse (softformula <* eof) filepath s