I believe this has been added to the board previously, but I'm unable to immediately find that task.

https://ticket.wikimedia.org/otrs/index.pl?Action=AgentTicketZoom;TicketID=11957557

To whom it may concern,

I’ve been using the Wikipedia app for a while and in that time I’d created several reading
lists of articles. However, while trying to add an article to one of the lists today I saw
that all of my reading lists and saved articles were gone. I did not delete them myself
and cannot find tips on recovering them, if such a thing is possible. I’m not sure if this
is a bug or something on my end that caused this.

Unfortunately, I don’t have any screenshots of my reading lists or saved articles from
before this happened, so all I can offer are these two of my now-empty lists (the lone
saved article is the one I was trying to save to a previously extant reading list).

I believe I had more than a dozen reading lists containing anywhere from 3 to 90+
articles. I do not have an account connected to the app.

If I need to provide any other information, please let me know.

Thank for you for time!