Google Flips The Switch On Smart App Updates In The Play Store [Video]

There seems to be quite a lot of movement happening behind the scenes at the Play Store - yesterday we discovered that Google Play Store gift cards and wishlist are getting prepped for launch, and today Google seems to have enabled those smart app updates that we've been salivating about since Google I/O.
Normally, when an update to an application comes out, the Play Store downloads it in full, which with large apps and slow connections can get quite painful (think 50MB+ sizes). Smart app updates, announced at an I/O session in June, was the solution. When enabled, only the incremental difference (a.k.a. the delta) between the old and new apks would be sent over the wire, thereby saving huge amounts of data for both Google and Play Store users.
Ladies and gentlemen, we have verified that these incremental "smart" updates went live recently, very likely last night or this morning, with the release of the 3.8.15 Play Store. Here's the good news: it should also work with earlier Play Store releases, like 3.7.15, as the change seems to be retroactive and server-side.
How about an example? The ezPDF Reader app weighs 6.34MB, but the delta is only about 2.7-3MB. It's even more drastic with Instagram's update from this morning - the Play Store only has to download about 3MB out of 13.

http://www.androidpolice.com/2012/08/16/google-flips-the-switch-on-smart-app-updates-in-the-play-store-video/