diff --git a/Data/Certificate/X509/Cert.hs b/Data/Certificate/X509/Cert.hs
index 4abfadf..15e7bf8 100644
--- a/Data/Certificate/X509/Cert.hs
+++ b/Data/Certificate/X509/Cert.hs
@@ -1,2 +1,3 @@
+{-# LANGUAGE FlexibleContexts #-}
 module Data.Certificate.X509.Cert
         (
diff --git a/Data/Certificate/X509/Ext.hs b/Data/Certificate/X509/Ext.hs
index 7595f14..8963a55 100644
--- a/Data/Certificate/X509/Ext.hs
+++ b/Data/Certificate/X509/Ext.hs
@@ -1,2 +1,3 @@
+{-# LANGUAGE FlexibleContexts #-}
 -- |
 -- Module      : Data.Certificate.X509.Ext
