diff --git a/ChangeLog b/ChangeLog
index 984380c18..3905d32b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -37,6 +37,8 @@
 2003-08-09  Jim Meyering  <jim@meyering.net>
 
 	* tests/misc/split-fail: Reflect that `split -a 0' is now accepted.
+	For tests of obsolete behavior, don't presume that unsetting
+	_POSIX2_VERSION is equivalent to _POSIX2_VERSION=199209.
 
 2003-08-07  Paul Eggert  <eggert@twinsun.com>