There are several apps that have updates available. However, the button to update all is greyed out. If I try to update the apps one at a time by tapping the update button, well it merely opens that app. I'm on an iPad 4, iOS 7.0.6. My iPhone 5s on iOS 7.1.2 works fine. My wife's iPad 3 on iOS 7.0.6 and iPhone 4S on iOS 7.0.6 won't update apps either. What's up?