diff --git a/Data/X509/CRL.hs b/Data/X509/CRL.hs
--- a/Data/X509/CRL.hs
+++ b/Data/X509/CRL.hs
@@ -9,6 +9,8 @@
 --
 -- follows RFC5280 / RFC6818.
 --
+{-# LANGUAGE FlexibleContexts #-}
+
 module Data.X509.CRL
     ( CRL(..)
     , RevokedCertificate(..)
diff --git a/Data/X509/Cert.hs b/Data/X509/Cert.hs
--- a/Data/X509/Cert.hs
+++ b/Data/X509/Cert.hs
@@ -7,6 +7,8 @@
 --
 -- X.509 Certificate types and functions
 --
+{-# LANGUAGE FlexibleContexts #-}
+
 module Data.X509.Cert (Certificate(..)) where
 
 import Data.ASN1.Types
diff --git a/Data/X509/Ext.hs b/Data/X509/Ext.hs
--- a/Data/X509/Ext.hs
+++ b/Data/X509/Ext.hs
@@ -7,6 +7,8 @@
 --
 -- extension processing module.
 --
+{-# LANGUAGE FlexibleContexts #-}
+
 module Data.X509.Ext
     ( Extension(..)
     -- * Common extension usually found in x509v3
diff --git a/x509.cabal b/x509.cabal
--- a/x509.cabal
+++ b/x509.cabal
@@ -1,5 +1,5 @@
 Name:                x509
-Version:             1.4.11
+Version:             1.4.12
 Description:         X509 reader and writer
 License:             BSD3
 License-file:        LICENSE