diff --git a/m4/README b/m4/README
index a4247d3..05e4069 100644
--- a/m4/README
+++ b/m4/README
@@ -2,7 +2,7 @@ README
 ======
 
 The following files were copied unmodified from the autoconf archive [1]
-(2011-12-21). Thanks.
+(2013-11-01). Thanks.
 
 [1]: http://www.gnu.org/software/autoconf-archive/