Android 8.1 Oreo appears to include a storage saving function that appears to cater to low storage devices. The feature was discovered in the Android Open Source Project framework; which details how the operating system will “downgrade” unused apps to increase space for system upgrades.
The idea is fairly straightforward. Android Oreo will keep tabs on how often each app is used, and mark those that haven’t been used for “x” amount of time. How much this happens to be isn’t defined at the moment. In any case, these marked apps will be in line for a downgrade in the event that the system runs out of storage.
As far as we can tell, the downgrade is a matter of clearing the cache from these unused apps. This is usually data that’s been temporarily created to run the app, and doesn’t quite impact its use. That said, the size of these caches can vary in size; going from only a few kilobytes to several hundred megabytes. Which means that the impact of this downgrade feature will not be the same for everyone.
This is likely to be something more useful for those not running around with flagship smartphones packing at least 64GB storage. Which, unfortunately, are the most likely devices to be receiving the first wave of updates to Android Oreo.
Comments at XDA Developers also note that OEMs will have to choose to enable to feature manually. Which could indicate that some phones may not see it at all.
[Source: XDA Developers]