First let me say, by SDK I'm not actually referring to QT Creator, but Ubuntu's QML libraries, I'm actually using Geany for all my programming.
When Ubuntu very first released the Ubuntu SDK I switched an app I was working on to QML, I'm using QML for the GUI and C for all the inner workings. After upgrading to 13.10 my app pretty much broke, it wasn't difficult for me to figure out what had changed with the Ubuntu SDK and make the appropriate changes, but now I am concerned about the SDK in general, did they only make such dramatic changes because their still working it out, or is every version of Ubuntu that comes out going to break compatibility with apps? In other words, once they get the Ubuntu SDK officially released is it going to be the same regardless what Ubuntu version people have?
And is there any word on when the final version of the Ubuntu SDK will be released?
The SDK was pretty fluid, since this was the initial development and we only reached our first "stable" state with the release of Ubuntu 13.10. There should not be any breakage in the API from here on out without first going to a deprecation period. If this is a concern to enough people, we can run a session at the upcoming UDS to discuss how to handle it.