This is the first time I've had to "migrate" an app from one version of Mac OS X to another. In the past, I had been compiling an app on 10.5. Everybody on 10.5 used it. When I started compiling for 10.6 (I waited until 10.6.3), I dropped support for 10.5, easy squeezy. Is there a common method for developers to implement new features for OS N, while still maintaining compatibility in the same binary for OS N-1? I want to avoid adding Lion features (full-screen mode, etc.) if there's no way for those apps to also run under Snow Leopard. How do developers handle this? Thanks!