Google has rolled out a new feature in the Play store that will save you time and data costs when downloading apps. Dubbed smart updates, the feature enables you to download only the updated part of the app from Google Play, instead of the entire package, as it was the case by now.
Also known as delta updates, the feature was announced at Google I/O in June and Android Police spotted it was enabled on Friday. So, for example, when you download the newly-released Instagram for Android update, instead of downloading the entire 13MB app, the delta/smart update will be only around 3MB.
Delta updates for Google Play apps have several advantages. First, if you are out of Wi-Fi range and you want to download an app, the toll on your data allowance wont be as substantial, helping you save on megabytes in the long run.
Perhaps the biggest advantage is that you will save time when downloading updates to large applications. Games in particular can easily run more than 500MB in size, and an update over a slow Wi-Fi connection can take hours. But with delta updates, you will download a much smaller file.
Its not easy to notice when you download a smart update, though. When you trigger an update, Google Play will still show the full size of the download package, but it will install the update as soon as the delta update has been downloaded. The feature does not seem to rely on the latest update of the Play store itself, as it appears to be implemented server-side with Google, so it should work with older versions as well.
Apples App Store does not have delta updates capabilities, and its unclear whether this feature will be part of the iOS 6 update arriving this fall. iOS does, however, make use of delta updates for system updates.