Google Play’s new Delta algorithm reduces download sizes of updates

We often let the updates’ notifications lie pending for days due to the amount of data they will consume in the process. Google Play store wants to fix this and is helping developers reduce app sizes and display the correct download size to users.

Google Play is introducing a new ‘Delta’ algorithm, according to which only changes (i.e deltas) for the designated APKs are downloaded and then merged with the existing parts of the app. What does this mean? It means that we will now download only a small part of the app that needs to update, instead of the whole APK.

This helps reduce the size of updates, making it less of a burden on users to get an updated app experience.

Elaborating on the reduction in app sizes, the official blog post mentions two patch updates for Google Chrome for Android. It shows that a major 22.8MB app update, from M46 to M47 has now been shrunk down to 12.9MB while, a 15.3MB(bigger than the current major update size) minor update of the M47 build has now been shrunk to a meager 3.6MB, using the new ‘Bsdiff’ delta algorithm.

The expanded delta and compression algorithms will now also let developers include large files up to 2GB in size within your app or game. This results in a reduction of major install sizes by 12 percent, and updates by 65 percent on average. Alongside reduction in app size, Google Play now also displays the actual size of the download or update in the description.

The new update is now live for almost 98 percent applications on the Google Play Store.