Index: UPGRADE.txt
===================================================================
RCS file: /cvs/drupal/drupal/UPGRADE.txt,v
retrieving revision 1.19
diff -u -p -r1.19 UPGRADE.txt
--- UPGRADE.txt	28 Jan 2010 07:09:03 -0000	1.19
+++ UPGRADE.txt	22 Apr 2010 05:11:59 -0000
@@ -49,7 +49,10 @@ Let's begin!
 
 4.  If using a custom or contributed theme, switch to Garland.
 
-5.  Disable all custom and contributed modules.
+5.  Disable all custom and contributed modules.  This includes any modules 
+    that are not listed under 'Core - required' or 'Core - optional' on
+    http://www.example.com/?q=admin/build/modules (replace www.example.com 
+    with your installation's domain name and path).
 
 6.  Remove all old files and directories from the Drupal installation directory.