http://lists.debian.org/debian-devel-ga ... 00213.html
This is quite old quote already, so it may not even be true anymore, but I find it quite disturbing anyway. Bullet is not truly backward compatible, so you have to stick with the version you have designed your program against. Using newer bullet without adjusting your program can lead to unwanted results.different versions of Bullet physics will have (slightly) different simulation behaviour. And once a game or app is tuned, you don't want to upgrade the physics anymore, it would break everything.
Do you think this is relevant to FreeOrion, or does it affect more the kind of games where programmer expects certain result from physics (adventure game where ball hitting a pillar causes something otherwise unreachable from top of the pillar to drop)? Should you list exact Bullet version that should be used instead of minimum version? Should correct version of bullet be included in FreeOrion source tree as suggested?