Re: 173 and xorg 1.10RCx support?
It's not a hard and fast rule, as became obvious with the recent 1.10 cycle. In any case, we still don't officially support RC or prerelease X servers. The advantage of freezing the ABI ahead of time is that we can build a driver and start it through the testing process before the final server release. The problem we had in the past was that we couldn't assume the server ABI was frozen until the day of the official release, which meant there was a delay that caused headaches for people.