diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+5.2.7:
+    * Fix -X option bug
+
 5.2.6:
     * Switch to optparse-applicative
 
diff --git a/hindent.cabal b/hindent.cabal
--- a/hindent.cabal
+++ b/hindent.cabal
@@ -1,5 +1,5 @@
 name:                hindent
-version:             5.2.6
+version:             5.2.7
 synopsis:            Extensible Haskell pretty printer
 description:         Extensible Haskell pretty printer. Both a library and an executable.
                      .
diff --git a/src/main/Main.hs b/src/main/Main.hs
--- a/src/main/Main.hs
+++ b/src/main/Main.hs
@@ -30,6 +30,7 @@
 import qualified System.IO as IO
 import           Options.Applicative hiding (action, style)
 import           Data.Monoid ((<>))
+import qualified Data.Text as T
 
 data Action = Validate | Reformat
 
@@ -103,7 +104,7 @@
       ) <*
       optional (strOption
            (long "style" <> help "Style to print with (historical, now ignored)" <> metavar "STYLE") :: Parser String)
-    exts = fmap getExtensions (many (option auto (short 'X' <> help "Language extension" <> metavar "GHCEXT")))
+    exts = fmap getExtensions (many (T.pack <$> strOption (short 'X' <> help "Language extension" <> metavar "GHCEXT")))
     indentSpaces =
         option auto
            (long "indent-size" <> help "Indentation size in spaces" <> value (configIndentSpaces config) <> showDefault) <|>