ios - Comparing creation/modification date of NSData objects -

at first have plist file in app bundle. @ point file can updated (downloaded documents folder). whats best way know file newer? mainbundle plist updated new app version , downloaded 1 oldest. have timestamp inside plist don't want load each of them memory able compare dates, each takes 1-2 seconds. there kind of creation date compare?

how this:

nserror *error = nil; nsdictionary* dict = [nsfilemanager attributesofitematpath:path error:&error]; nsdate* date = [dict filemodificationdate];