1 - put all your patches in a 'patch_vN-vN+1.sql' or .sh file
    (see patch_0.5-0.6.sql for example)
2 - take a dump from the production server and put it on preprod server
3 - apply the patch, test and install the new version

if ok :

4 - write the version in ZEN.py
5 - update the Changelog file
6 - commit all that stuff
7 - tag the cvs version ZEN and libcommonZope, example : 
		"cvs tag (-b) 'v0-6'" for version 0.6 of Zen
		"cvs tag (-b) 'v1-6'" for version 1.6 of libcommonZope

	It will be the version for the prod server.