As with all software version upgrades, going from XenApp 5 to XenApp 6.5 could induce mild "console-itis" - that bothersome feeling that comes from trying to find out where all the stuff in the old version has been moved to (and thereby effectively hidden) in the new version. If you are seeing a XenApp 6 or 6.5 farm for the first time, follow the rule "everything is a policy now," and you'll discover that most of the farm property settings are in the new "AppCenter."