Google and most of the developers push up a new update for their app frequently, but now Google wants these app updates smaller. Now the app updates will be in the form of Patches, which is smaller and consumes less data than actual update. Google has just rolled out a new delta algorithm called Bsdiff, for the Play Store. Bsdiff can make app updates 50% smaller than actual update in the form of patch.
|Patch Description||Previous patch size||Bsdiff Size|
|M46 to M47 major update||22.8 MB||12.9 MB|
|M47 minor update||15.3 MB||3.6 MB|
APK Expansion Files allow developers to include additional large files up to 2GB in size (e.g. high resolution graphics or media files) with your app, which is especially popular with games. Google recently expanded their delta and compression algorithms to apply to these APK Expansion Files in addition to APKs, reducing the download size of initial installs by 12%, and updates by 65% on average.
Source: Android Blog