diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,8 @@
+## 0.3.0.4
+
+* Warning cleanup
+* Colorize diffs
+
 ## 0.3.0.3
 
 * Diffs against previous versions
diff --git a/mega-sdist.cabal b/mega-sdist.cabal
--- a/mega-sdist.cabal
+++ b/mega-sdist.cabal
@@ -1,34 +1,47 @@
-Name:                mega-sdist
-Version:             0.3.0.3
-Synopsis:            Handles uploading to Hackage from mega repos
-Description:         See README.md
-Homepage:            https://github.com/snoyberg/mega-sdist
-License:             MIT
-License-file:        LICENSE
-Author:              Michael Snoyman
-Maintainer:          michael@snoyman.com
-Category:            Distribution
-Build-type:          Simple
-Cabal-version:       >=1.8
-extra-source-files:  README.md ChangeLog.md
+-- This file has been generated from package.yaml by hpack version 0.20.0.
+--
+-- see: https://github.com/sol/hpack
+--
+-- hash: 2563f862ebfe95c1677871684a68b2b6e9ad380b37504e43d4df5a90efb9b749
 
-Executable mega-sdist
-  Main-is:             mega-sdist.hs
-  other-modules:       Paths_mega_sdist
-  Build-depends:       base             >= 4              && < 5
-                     , classy-prelude-conduit >= 1.2
-                     , conduit-extra
-                     , http-conduit     >= 2.2.3
-                     , tar-conduit
-                     , directory
-                     , filepath
-                     , typed-process
-                     , yaml
-                     , optparse-simple
-                     , temporary
-                     , bytestring
-                     , text
+name:           mega-sdist
+version:        0.3.0.4
+synopsis:       Handles uploading to Hackage from mega repos
+description:    See README.md
+category:       Distribution
+homepage:       https://github.com/snoyberg/mega-sdist#readme
+bug-reports:    https://github.com/snoyberg/mega-sdist/issues
+author:         Michael Snoyman
+maintainer:     michael@snoyman.com
+license:        MIT
+license-file:   LICENSE
+build-type:     Simple
+cabal-version:  >= 1.10
 
+extra-source-files:
+    ChangeLog.md
+    README.md
+
 source-repository head
-  type:     git
-  location: https://github.com/snoyberg/mega-sdist.git
+  type: git
+  location: https://github.com/snoyberg/mega-sdist
+
+executable mega-sdist
+  main-is: mega-sdist.hs
+  build-depends:
+      base >=4 && <5
+    , bytestring
+    , classy-prelude-conduit >=1.2
+    , conduit-extra
+    , directory
+    , filepath
+    , http-conduit >=2.2.3
+    , optparse-simple
+    , tar-conduit
+    , temporary
+    , text
+    , typed-process
+    , yaml
+  other-modules:
+      Paths_mega_sdist
+  default-language: Haskell2010
diff --git a/mega-sdist.hs b/mega-sdist.hs
--- a/mega-sdist.hs
+++ b/mega-sdist.hs
@@ -12,8 +12,9 @@
 import System.FilePath
 import Data.Conduit.Binary (sinkFileCautious)
 import Data.Yaml (Value (..), decodeEither')
-import Options.Applicative.Simple
-import Paths_mega_sdist (version)
+import Options.Applicative.Simple hiding (header, value)
+import qualified Paths_mega_sdist as Paths (version)
+import System.IO (hIsTerminalDevice)
 import System.IO.Temp (withSystemTempDirectory)
 import qualified Data.ByteString.Lazy as L
 import Data.Semigroup (Max (..), Option (..))
@@ -49,7 +50,7 @@
 main :: IO ()
 main = do
     (Args {..}, ()) <- simpleOptions
-        $(simpleVersion version)
+        $(simpleVersion Paths.version)
         "Check Haskell cabal package versions in a mega-repo"
         "Determines if the code present in this repo is the most current with Hackage"
         (Args
@@ -101,13 +102,15 @@
             mapM_ sayPackage $ keys s
             mapM_ (removeFile . packageFile) $ keys s
 
+    toColor <- hIsTerminalDevice stdout
+
     case lookup DoesNotExist m of
         Nothing -> return ()
         Just s -> do
             say "\nThe following new packages exist locally:"
             forM_ (mapToList s) $ \(name, mdiff) -> do
                 sayPackage name
-                forM_ mdiff (L.hPut stdout)
+                sayDiff toColor mdiff
 
     case lookup NeedsVersionBump m of
         Nothing -> do
@@ -123,8 +126,12 @@
             say "\nThe following packages require a version bump:"
             forM_ (mapToList s) $ \(name, mdiff) -> do
                 sayPackage name
-                forM_ mdiff (L.hPut stdout)
+                sayDiff toColor mdiff
 
+sayDiff :: Bool -- ^ use color?
+        -> Maybe Diff -> IO ()
+sayDiff toColor = mapM_ $ L.hPut stdout . (if toColor then colorize else id)
+
 data Status = DoesNotExist | NoChanges | NeedsVersionBump
     deriving (Show, Eq, Ord)
 
@@ -145,8 +152,8 @@
         if localFileExists
             then handleFile
             else do
-                reqH <- getUrlHackage package
-                runResourceT $ httpSink reqH $ \resH -> do
+              reqH <- getUrlHackage package
+              runResourceT $ httpSink reqH $ \resH -> do
                 case () of
                   ()
                     | getResponseStatusCode resH `elem` [403, 404] -> do
@@ -174,9 +181,9 @@
 getLatestVersion :: MonadIO m => PackageName -> m (Maybe (FilePath, Version))
 getLatestVersion name = liftIO $ do
     stack <- getAppUserDataDirectory "stack"
-    let index = stack </> "indices" </> "Hackage" </> "00-index.tar"
+    let indexTar = stack </> "indices" </> "Hackage" </> "00-index.tar"
     mversion <- runConduitRes
-        $ sourceFile index
+        $ sourceFile indexTar
        .| untar
        .| withEntries yield
        .| foldMapC (parseVersionNumber name)
@@ -276,7 +283,7 @@
                         , unpack (unVersion v)
                         ]
                 (_, out, _) <- readProcess $ setWorkingDir diff $ proc "diff"
-                    [ "-r"
+                    [ "-ru"
                     , "old" </> toNV av
                     , "new" </> toNV bv
                     ]
@@ -306,3 +313,24 @@
             lbs <- sinkLazy
             yield $ asMap $ singletonMap (headerFilePath header) lbs
         | otherwise = return ()
+
+colorize :: LByteString -> LByteString
+colorize =
+    intercalate "\n" . map colorLine . L.split 10
+  where
+    colorLine :: LByteString -> LByteString
+    colorLine l =
+      case (toEnum . fromEnum) <$> headMay l of
+        Just '-' -> add "31" l
+        Just '+' -> add "32" l
+        Just '@' -> add "34" l
+        _ -> l
+
+    add :: LByteString -> LByteString -> LByteString
+    add color l = concat
+      [ "\x1b["
+      , color
+      , "m"
+      , l
+      , "\x1b[0m"
+      ]