With new version there is always few enhancements and product defects which are corrected. this holds same for clients as well. The manager should be capable of interpreting new logs which are sent by the clients.
Thats the reason you have to first upgrade your manager , then upgrade the clients.
instead of 11.0.7 i would suggest to upgrade to 12.1 , the latest version.
http://www.symantec.com/business/support/index?page=content&id=TECH163602