# Tweet by [@keefmoon](http://twitter.com/keefmoon) on 2010-04-10 11:42:02 > [!INFO] Archived from [original tweet](http://twitter.com/keefmoon/status/11933179405) In reply to: [@andiih](http://twitter.com/andiih/status/11932736087) @andiih What do you mean by 4.0 SDK native code only? You have code a 4.0 app or not? No Backward compatibility?