Google is making it mandatory for new Android 11 devices to have support for ‘seamless updates’, as revealed by a report from XDA Developers. The report is based on a key discovery in relation to the A/B partition system updates.
The A/B system updates have been around for some time now, introduced by Google along with Android 7.0 Nougat. According to the Android developer page, to support A/B system updates, devices need two virtual partitions that are duplicates of each other.
The system update is downloaded on the inactive partition, while users have access to the other partition. When the update is installed on the inactive partition and users reboot their device, the partitions swap places.
The updated partition is booted up and becomes the active one while the other partition is left as it is. So, if there are any errors encountered on an update, the device will simply boot up the old version partition. Additionally, the update doesn’t require cache or even storage space on the device as it can be simply streamed on the device.
In short, A/B system updates allow users to have access to their devices while their system is being updated, thus seamless updates.
The key discovery about it was a commit message on the AOSP Gerrit submitted by Yifan Hong, a software engineer at Google on the Project Treble team stating, “Require Virtual A/B on R launches” which can be interpreted as mandatory seamless update support required on future Android 11 devices.