Gmail for iOS has been updated to version 3.0, adding background refresh to make viewing your email faster. While Gmail already utilizes push notifications, users have previously needed to wait for the app to refresh and load new messages when opening it.
Background refresh is part of what allows any iOS 7 app for iPhone or iPad to appear to be multitasking all the time. The truth is, they're really multitasking "just in time" by updating in the background whenever they have the opportunity or right before they figure you'll be launching them. In spite of how efficient Apple has tried to make it, however, using background refresh will also use more power and consume more data. Luckily, if either your battery life or your data limit is running low you can turn off background refresh, either entirely or just for those apps you don't consider that important.
Like much the internet, we're getting flooded with messages from people who're finding themselves repeatedly logged out of Mailbox, Snapchat (we don't judge!), and other apps following the iOS 7 update. Not only can that be tedious, but in some cases the apps demand the entire setup process be repeated, which can be a showstopper. A bug in Apple's new background update API could be the culprit, according to Ellis Hamberger at The Verge: