diff --git a/pep-0101.txt b/pep-0101.txt
index 7de13d38a..0942a485d 100644
--- a/pep-0101.txt
+++ b/pep-0101.txt
@@ -200,6 +200,11 @@ How to Make A Release
 
       $ .../release/release.py --tag X.Y.ZaN
 
+      NOTE: when forward, i.e. "null" merging your changes to newer branches,
+      e.g. 2.6 -> 2.7, do *not* revert your changes to the .hgtags file or you
+      will not be able to run the --export command below.  Revert everything
+      else but leave .hgtags alone.
+
   ___ If this is a final major release, branch the tree for X.Y.
 
       When making a major release (e.g., for 3.2), you must create the