Reminds me of when I first started working with SQL Server. If you installed SQL 6.5 on Windows NT above a certain service pack level, you'd get a "not tested on this operating system" warning.

This is an example of "Not supported" meaning anthing from "won't install" to "it might work fine, but we're not promising that." SQL 2008 R2 Enterprise is "Not Supported" on Windows 7, but have an instance installed there and have tested several Enterprise features successfully.