While not everyone is thrilled with the way Apple handled the release, it turns out that Snow Leopard is Apple’s most compatible operating system release ever. According to sources familiar with Snow Leopard’s internal testing process, Apple kept an enormous amount of statistics on third-party application compatibility.
They said that Apple not only tracked many of the most widely-used apps, they tracked many of the shareware apps, as well. If an application exhibited problems, the developers were notified of the incompatibility and were offered help to make it Snow Leopard-compliant.
It’s true that Apple did not offer a public beta of Snow Leopard, but it did expand the seed program with this release. Some large and small businesses, as well as individuals were included in the beta program for Snow Leopard. Of course, developers have access to the code through Apple’s Developer Program, to test their apps through the entire process.
Apple began working with developers in June 2008, according to my source. This gave developers the maximum amount of time to check their apps against the new operating system.