diff --git a/.travis.yml b/.travis.yml
index e1402ac..c5d47fb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,8 +9,6 @@ cache:
 
 matrix:
   include:
-    - env: CABALVER=1.24 GHCVER=7.6.3
-      addons: {apt: {packages: [cabal-install-1.24,ghc-7.6.3], sources: [hvr-ghc]}}
     - env: CABALVER=1.24 GHCVER=7.8.4
       addons: {apt: {packages: [cabal-install-1.24,ghc-7.8.4,],sources: [hvr-ghc]}}
     - env: CABALVER=1.24 GHCVER=7.10.3
@@ -33,10 +31,6 @@ script:
     *)      cabal configure --enable-tests -v2 -f dev ;;
    esac
  - cabal build
- - case "$GHCVER" in
-    "7.6.3") true ;;
-    *)       cabal test --show-details=always ;;
-   esac
  - cabal sdist
  - cabal haddock | grep "100%" | wc -l | grep "13"
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 26b542d..e268061 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Inflections 0.4.0.0
+
+* Update megaparsec to version 6.
+
 ## Inflections 0.3.0.0
 
 * A more type-safe API forbidding creation of invalid words.
diff --git a/Text/Inflections.hs b/Text/Inflections.hs
index 4d1a349..04b6c60 100644
--- a/Text/Inflections.hs
+++ b/Text/Inflections.hs
@@ -117,6 +117,7 @@ where
 
 import Control.Monad.Catch (MonadThrow (..))
 import Data.Text (Text)
+import Data.Void (Void)
 import Text.Inflections.Camelize (camelize, camelizeCustom)
 import Text.Inflections.Dasherize (dasherize)
 import Text.Inflections.Data (Transliterations, defaultTransliterations)
@@ -141,7 +142,7 @@ import Prelude hiding (Word)
 --
 -- >>> toUnderscore "FooBarBazz"
 -- "foo_bar_bazz"
-toUnderscore :: Text -> Either (ParseError Char Dec) Text
+toUnderscore :: Text -> Either (ParseError Char Void) Text
 toUnderscore = fmap underscore . parseCamelCase []
 
 -- | Transforms CamelCasedString to snake-cased-string-with-dashes.
@@ -150,7 +151,7 @@ toUnderscore = fmap underscore . parseCamelCase []
 --
 -- >>> toDashed "FooBarBazz"
 -- "foo-bar-bazz"
-toDashed :: Text -> Either (ParseError Char Dec) Text
+toDashed :: Text -> Either (ParseError Char Void) Text
 toDashed = fmap dasherize . parseCamelCase []
 
 -- | Transforms underscored_text to CamelCasedText. If first argument is
@@ -166,7 +167,7 @@ toDashed = fmap dasherize . parseCamelCase []
 toCamelCased
   :: Bool               -- ^ Capitalize the first character
   -> Text               -- ^ Input
-  -> Either (ParseError Char Dec) Text -- ^ Output
+  -> Either (ParseError Char Void) Text -- ^ Output
 toCamelCased c = fmap (camelizeCustom c) . parseSnakeCase []
 
 -- | Transforms underscored_text to space-separated human-readable text.
@@ -185,10 +186,10 @@ toCamelCased c = fmap (camelizeCustom c) . parseSnakeCase []
 toHumanized
   :: Bool               -- ^ Capitalize the first character
   -> Text               -- ^ Input
-  -> Either (ParseError Char Dec) Text -- ^ Output
+  -> Either (ParseError Char Void) Text -- ^ Output
 toHumanized c = fmap (humanizeCustom c) . parseSnakeCase []
 
--- | Lift something of type @'Either' ('ParseError' 'Char' 'Dec') a@ to
+-- | Lift something of type @'Either' ('ParseError' 'Char' 'Void') a@ to
 -- an instance of 'MonadThrow'. Useful when you want to shortcut on parsing
 -- failures and you're in an instance of 'MonadThrow'.
 --
@@ -196,6 +197,6 @@ toHumanized c = fmap (humanizeCustom c) . parseSnakeCase []
 --
 -- /since 0.3.0.0/
 
-betterThrow :: MonadThrow m => Either (ParseError Char Dec) a -> m a
+betterThrow :: MonadThrow m => Either (ParseError Char Void) a -> m a
 betterThrow (Left err) = throwM (InflectionParsingFailed err)
 betterThrow (Right  x) = return x
diff --git a/Text/Inflections/Parse/CamelCase.hs b/Text/Inflections/Parse/CamelCase.hs
index 340d93b..baeef76 100644
--- a/Text/Inflections/Parse/CamelCase.hs
+++ b/Text/Inflections/Parse/CamelCase.hs
@@ -19,9 +19,10 @@ where
 
 import Control.Applicative
 import Data.Text (Text)
+import Data.Void (Void)
 import Text.Inflections.Types
 import Text.Megaparsec
-import Text.Megaparsec.Text
+import Text.Megaparsec.Char
 import qualified Data.Text as T
 
 #if MIN_VERSION_base(4,8,0)
@@ -31,6 +32,8 @@ import Data.Foldable
 import Prelude hiding (elem)
 #endif
 
+type Parser = Parsec Void Text
+
 -- | Parse a CamelCase string.
 --
 -- >>> bar <- mkAcronym "bar"
@@ -44,7 +47,7 @@ import Prelude hiding (elem)
 parseCamelCase :: (Foldable f, Functor f)
   => f (Word 'Acronym) -- ^ Collection of acronyms
   -> Text              -- ^ Input
-  -> Either (ParseError Char Dec) [SomeWord] -- ^ Result of parsing
+  -> Either (ParseError Char Void) [SomeWord] -- ^ Result of parsing
 parseCamelCase acronyms = parse (parser acronyms) ""
 
 parser :: (Foldable f, Functor f)
@@ -59,7 +62,7 @@ acronym :: (Foldable f, Functor f)
   => f (Word 'Acronym)
   -> Parser (Word 'Acronym)
 acronym acronyms = do
-  x <- T.pack <$> choice (string . T.unpack . unWord <$> acronyms)
+  x <- choice (string . unWord <$> acronyms)
   case mkAcronym x of
     Nothing -> empty -- cannot happen if the system is sound
     Just acr -> return acr
diff --git a/Text/Inflections/Parse/SnakeCase.hs b/Text/Inflections/Parse/SnakeCase.hs
index 19d6a24..cbd6782 100644
--- a/Text/Inflections/Parse/SnakeCase.hs
+++ b/Text/Inflections/Parse/SnakeCase.hs
@@ -18,9 +18,10 @@ where
 
 import Control.Applicative
 import Data.Text (Text)
+import Data.Void (Void)
 import Text.Inflections.Types
 import Text.Megaparsec
-import Text.Megaparsec.Text
+import Text.Megaparsec.Char
 import qualified Data.Text as T
 
 #if MIN_VERSION_base(4,8,0)
@@ -30,6 +31,8 @@ import Data.Foldable
 import Prelude hiding (elem)
 #endif
 
+type Parser = Parsec Void Text
+
 -- | Parse a snake_case string.
 --
 -- >>> bar <- mkAcronym "bar"
@@ -43,7 +46,7 @@ import Prelude hiding (elem)
 parseSnakeCase :: (Foldable f, Functor f)
   => f (Word 'Acronym) -- ^ Collection of acronyms
   -> Text              -- ^ Input
-  -> Either (ParseError Char Dec) [SomeWord] -- ^ Result of parsing
+  -> Either (ParseError Char Void) [SomeWord] -- ^ Result of parsing
 parseSnakeCase acronyms = parse (parser acronyms) ""
 
 parser :: (Foldable f, Functor f)
diff --git a/Text/Inflections/Types.hs b/Text/Inflections/Types.hs
index 06b42f5..b13edba 100644
--- a/Text/Inflections/Types.hs
+++ b/Text/Inflections/Types.hs
@@ -33,6 +33,7 @@ where
 import Control.Monad.Catch
 import Data.Char (isAlphaNum)
 import Data.Data (Data)
+import Data.Void (Void)
 import Data.Text (Text)
 import Data.Typeable (Typeable)
 import GHC.Generics (Generic)
@@ -135,7 +136,7 @@ instance Transformable (Word 'Acronym) where
 -- /since 0.3.0.0/
 
 data InflectionException
-  = InflectionParsingFailed (ParseError Char Dec)
+  = InflectionParsingFailed (ParseError Char Void)
   | InflectionInvalidWord Text
   | InflectionInvalidAcronym Text
   deriving (Eq, Show, Typeable, Data, Generic)
diff --git a/inflections.cabal b/inflections.cabal
index c3a2222..661fd81 100644
--- a/inflections.cabal
+++ b/inflections.cabal
@@ -1,5 +1,5 @@
 name:                inflections
-version:             0.3.0.0
+version:             0.4.0.0
 synopsis:            Inflections library for Haskell
 description:
   Inflections provides methods for singularization, pluralization,
@@ -49,9 +49,12 @@ library
     ghc-options:      -O2 -Wall
   build-depends:       base         >= 4.6   && < 5.0
                      , exceptions   >= 0.6   && < 0.9
-                     , megaparsec   >= 5.0   && < 6.0
+                     , megaparsec   >= 6.0   && < 7.0
                      , text         >= 0.2   && < 1.3
                      , unordered-containers >= 0.2.7 && < 0.3
+  if !impl(ghc >= 7.10)
+    build-depends:      void         == 0.7.*
+
   default-language:    Haskell2010
 
 test-suite test
@@ -61,10 +64,17 @@ test-suite test
   build-depends:       inflections
                      , QuickCheck   >= 2.7.6 && < 3.0
                      , base         >= 4.6   && < 5.0
+                     , containers   >= 0.5   && < 0.7
                      , hspec        >= 2.0   && < 3.0
-                     , hspec-megaparsec >= 0.3 && < 0.4
-                     , megaparsec   >= 5.1   && < 6.0
+                     , hspec-megaparsec >= 1.0 && < 2.0
+                     , megaparsec
                      , text         >= 0.2   && < 1.3
+  if !impl(ghc >= 7.10)
+    build-depends:      void         == 0.7.*
+
+  if !impl(ghc >= 8.0)
+    build-depends:      semigroups   == 0.18.*
+
   if flag(dev)
     ghc-options:      -Wall -Werror
   else
diff --git a/stack.yaml b/stack.yaml
index 9085c49..1ec4e2b 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,6 +1,7 @@
+---
 resolver: lts-7.13
-packages:
-- '.'
+
 extra-deps:
-- hspec-megaparsec-0.3.0
-- megaparsec-5.1.2
+  - hspec-megaparsec-1.0.0
+  - megaparsec-6.0.0
+  - parser-combinators-0.1.0
diff --git a/test/Text/InflectionsSpec.hs b/test/Text/InflectionsSpec.hs
index 84797ec..4437b4f 100644
--- a/test/Text/InflectionsSpec.hs
+++ b/test/Text/InflectionsSpec.hs
@@ -1,10 +1,44 @@
+{-# LANGUAGE CPP               #-}
 {-# LANGUAGE OverloadedStrings #-}
 
 module Text.InflectionsSpec (spec) where
 
+import Data.Void
 import Test.Hspec
 import Test.QuickCheck
 import Text.Inflections
+import Text.Megaparsec
+
+import qualified Data.List.NonEmpty as NE
+import qualified Data.Set as S
+
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative
+#endif
+
+arbitraryParseError :: Gen (ParseError Char Void)
+arbitraryParseError = oneof [trivialError, fancyError]
+    where
+      trivialError = TrivialError <$> nonEmptyArbitrary <*> maybeErrorItem <*> setErrorItem
+      fancyError = FancyError <$> nonEmptyArbitrary <*> setErrorFancy
+      nonEmptyArbitrary = NE.fromList <$> listOf1 arbitrarySourcePos
+      setErrorFancy = S.fromList <$> listOf arbitraryErrorFancy
+      maybeErrorItem = oneof [ Just <$> arbitraryErrorItem, return Nothing]
+      setErrorItem = S.fromList <$> listOf arbitraryErrorItem
+
+arbitrarySourcePos :: Gen SourcePos
+arbitrarySourcePos = SourcePos <$> arbitrary <*> posArbitrary <*> posArbitrary
+    where
+      posArbitrary = mkPos <$> ((+1) . abs <$> arbitrary)
+
+arbitraryErrorFancy :: Gen (ErrorFancy e)
+arbitraryErrorFancy = oneof [ ErrorFail <$> arbitrary ]
+
+arbitraryErrorItem :: (Arbitrary e) => Gen (ErrorItem e)
+arbitraryErrorItem = oneof [ tokens_, labels_, return EndOfInput ]
+    where
+      tokens_ = Tokens <$> (NE.fromList <$> listOf1 arbitrary)
+      labels_ = Label <$> (NE.fromList <$> listOf1 arbitrary)
 
 spec :: Spec
 spec = do
@@ -38,9 +72,10 @@ spec = do
   describe "betterThrow" $ do
     context "when given a parse error" $
       it "throws the correct exception" $
-        property $ \err ->
+        property $ forAll arbitraryParseError $ \err ->
           betterThrow (Left err) `shouldThrow`
             (== InflectionParsingFailed err)
+
     context "when given a value in Right" $
       it "returns the value" $
         property $ \x ->