# 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?