hi.
Kindly provide SEP 12.x upgrade Installation Steps and document.
you can check this artical and forums.
http://www.symantec.com/business/support/index?page=content&id=TECH163580
http://www.symantec.com/business/support/index?page=content&id=TECH163602
http://www.symantec.com/business/support/index?page=content&id=TECH163112
https://www-secure.symantec.com/connect/articles/sep-11x-sep-121-upgrade-process-graphical-overview
https://www-secure.symantec.com/connect/forums/plan-action
thanks
thanks providing step our company postpone the upgradation plan .