diff --git a/src/Text/Pandoc/Writers/OpenDocument.hs b/src/Text/Pandoc/Writers/OpenDocument.hs
index 773d142f4..901f827fb 100644
--- a/src/Text/Pandoc/Writers/OpenDocument.hs
+++ b/src/Text/Pandoc/Writers/OpenDocument.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE PatternGuards, OverloadedStrings #-}
+{-# LANGUAGE PatternGuards, OverloadedStrings, FlexibleContexts #-}
 {-
 Copyright (C) 2008-2014 Andrea Rossato <andrea.rossato@ing.unitn.it>
                         and John MacFarlane.