diff --git a/HsColour.hs b/HsColour.hs
--- a/HsColour.hs
+++ b/HsColour.hs
@@ -29,6 +29,7 @@
               , ("print-css", Information)
               , ("html",   Format HTML)
               , ("css",    Format CSS)
+              , ("acss",   Format ACSS)
               , ("icss",   Format ICSS)
               , ("tty",    Format TTY)
               , ("tty256", Format (TTYg XTerm256Compatible))
diff --git a/hscolour.cabal b/hscolour.cabal
--- a/hscolour.cabal
+++ b/hscolour.cabal
@@ -1,6 +1,6 @@
 Name: hscolour
-Version: 1.24.1
-Copyright: 2003-2016 Malcolm Wallace; 2006 Bjorn Bringert
+Version: 1.24.2
+Copyright: 2003-2017 Malcolm Wallace; 2006 Bjorn Bringert
 Maintainer: Malcolm Wallace
 Author: Malcolm Wallace
 Homepage: http://code.haskell.org/~malcolm/hscolour/