I think a backup function is a must in an app of this type.
The best backup type is to syncronize with google account so if you have 2 device you can read on any of the two and the other one update with the readed chapter and new novels added.
If it's too long to do or complicated a backup in a file is a good alternative, maybe with option to upload in a cloud service like:
Box
One drive
Google drive
ftp server
http server
Etc..
I think a backup function is a must in an app of this type.
The best backup type is to syncronize with google account so if you have 2 device you can read on any of the two and the other one update with the readed chapter and new novels added.
If it's too long to do or complicated a backup in a file is a good alternative, maybe with option to upload in a cloud service like:
Box
One drive
Google drive
ftp server
http server
Etc..