One huge downside of iBooks is that it would happily deauthorize access to the (DRM free) epub files you’ve added to the app manually after a couple of days wit

One huge downside of iBooks is that it would happily deauthorize access to the (DRM free) epub files you’ve added to the app manually after a couple of days without internet connection. I made a mistake of going on a long distance hiking trip and thinking can read some books in the tent before falling asleep. Nope, eBooks refused me until I returned to the mobile coverage area and resynced my library with their cloud service. I switched to an offline-first 3rd party app immediately after.