The next couple of versions will focus in getting reed of any existing issue, then I will resume working on this feature.
I may have found a solution to handle the charge necessary and which might not cost too much.
Once a first beta with basic subscription syncing is available I will study the impact on the servers (and the cost), then I will add more syncing step by step, in order to sync the read status, favorite flag, playback progress, …
Hopefully I’ll be able to add this feature in the free versionAnonymous commented
Why not sync the data to Google Drive on Android, and whatever cloud service is naturally available in iOS? This should have zero cost to you, since it uses bandwidth and space from the user.