On the day after I upgraded the OS on my iPhone 3Gs and iPod Touch 2nd Gen I also upgraded an app on those two devices & on my iPad (no upgraded OS until Fall.) The app works as expected on the two OS4 devices but crashes when opening on the iPad. I now have 22 (and increasing daily) apps which have been updated for OS4 sitting in the App Store app on my iPad. I'm holding off installing any of the updated apps for fear of losing the functionality that I currently have. Is anyone else paddling around in my boat? I have no problem waiting but it occurred to me that it was crummy that an app would no longer work on an OS3 device after the update unless the difference is something built in to allow for the multi-tasking feature. Fall is too long to have to wait for full featured use.