When upgrading from 3.9.5 to 3.9.6, we saw that all books in My Books were cleared from device (see attached video). 

The expectation is that books that have Axis DRM and do not have an expiration (or are expired) are cleared on a regular basis, including on app upgrades. All other books should remain on the device when cleaning up expired books. 

However, the minimum requirement for the feature is that books that do not have an expiration date, DRM or not, could be deleted, but exactly once on initial app upgrade; not a regular task. 

Either of the above options are viable for a solution, but it seems the current behavior is deleting more aggressively than intended.