Aspyr says it will phase out support for Snow Leopard once Mavericks is out in the world. Aspyr is the publisher of Mac versions of AAA game releases like Bioshock Infinite, Civilization V and Borderlands 2. The news comes from Aspyr's GameAgent blog.
This means all future releases of Aspyr games, as well as any patches and updates for existing Aspyr games, will no longer be supported on Mac OS X 10.6 (Snow Leopard); in some instances, older titles that receive updates or patches may cease to work on OS X 10.6. To continue to play the latest Mac games, we recommend upgrading your computer or operating system to the latest version of OS X.
Snow Leopard has, up to now, been the baseline level of support for many of Aspyr's games. But Mavericks necessitates changes, and Aspyr says that its efforts are best spent with forward compatibility, rather than backward.
Currently 8% of our existing audience is on Mac OS X 10.6, down from 16% in January. With the release of Mavericks we anticipate this reducing further, and therefore we believe our efforts should be focused on supporting the growing audience.
It'll be interesting to see how many other Mac software developers follow suit after Mavericks is released. The latest reports indicate that Apple will release Mavericks in late October.