So, maybe you can get to it in a couple of days. Fix what you can using the old SDK before GM build becomes available. Then you have a small amount of updates once apps using the new SDK can be submitted. The app will be temporarily broken for a few days on a brand new OS until the update goes live. Is that really a big deal? The world doesn't come to an end if you get a few bad reviews from impatient users. I remember being in the mobile app development rat race and am so glad I left that world behind. Too much daily panic about things that really don't matter much.