Quick question - is it true that Cleanup is not very usefull on Android 6.x because of new system permission in latest Android it can’t reach and clean caches anymore? 
Hi,
if user grants Cleanup a permission to access storage, we can still clean the caches except the internal caches. Those are not accessible trough API and can be deleted only by manual action of user in system settings (called Storage and USB on my Nexus 5x).
We are considering a feature that leads user from Cleanup to settings and tell him how to delete that
Cheers.
is this the reason why memory boost always say cleanup of 0. Using Nexus 6 running Android N
Hi,
Cleanup is not supporting Android 7 yet, it was released only as a developer preview so far.
We will release an adjustment for Android 7 close to final release of that operating system.