there's a way to know the minimum dash/kernel version needed by a game?
I believe the update depends on which Wave the game is. Each "wave" is a new update added to the video region on the disc. Not all dashboard updates are released as games. So the August 09 update is the fourth to be packaged with games.
If you want to play newer games but keep the console exploitable, you have to use FreeBoot to boot the later consoles while having 7371 installed. If the console is no longer exploitable (summer upate or later installed) then it can no longer be exploited, take the latest updates and play your games. The latest dashboards do prevent you from playing backups with a modded DVD drive.