Android too offers excellent forward compatibility! It is easy, as API changes are generally additive. I challenge you to find a few different apps written for, say, Android 1.6 that don't run on 4.0. I am sure some examples exist, but they are rare. In fact, I would even argue that Windows apps fail more often to be forward compatible than Android apps, because of the sheer complexity of the Windows software stack compared to Android.
As to backward compatibility, just like on Windows, it is the developers' responsibility to ensure he refrains from using APIs that are too recent. For example, if you write a Windows Direct3D 10 game, it won't run on XP because this API is only available on Vista and up. Same thing for Android: select the right API level when developing your app! http://developer.android.com/guide/appendix/api-levels.html How is Windows better/different than Android in this respect?
I speak from experience. I have developed on both Windows and Android, contrary to most people in this thread.
As to backward compatibility, just like on Windows, it is the developers' responsibility to ensure he refrains from using APIs that are too recent. For example, if you write a Windows Direct3D 10 game, it won't run on XP because this API is only available on Vista and up. Same thing for Android: select the right API level when developing your app! http://developer.android.com/guide/appendix/api-levels.html How is Windows better/different than Android in this respect?
I speak from experience. I have developed on both Windows and Android, contrary to most people in this thread.