Will Windows Phone 8 app run on Windows Phone 7?

Question

I have some apps developed with Windows Phone SDK 7.1 which undoubtedly run on Windows Phone 8 without any change.

My question is the other way. If I upgrade my app WP7 apps to WP8, meaning I make necessary namespace changes and compile them with WP8 SDK, will they still run on WP7? - I guess no.

What should be my strategy to have apps that run on both of the OS and still I should be able to use advanced functionality (if it runs on WP8) that WP8 offers (like Wallet, NFC, Nokia Imaging and more stuff like that)?

Is that I need to create 2 separate versions of each app? One will run on WP7 built with WP7 SDK and will not have advanced functionality like Wallet, NFC Sharing. The other app will have all of them and built with WP8. Will they be two separate apps in Windows Phone Marketplace?

Answer 1

Windows Phone 7 apps will run on Windows Phone 8, but the reverse is not possible. The former is called backwards compatibility.

If you want to support WP 7 OS, you need to maintain two different applications and submit them independently to the store.