Lost my WHOLE Library in this update!

I love ShuBook SE and use it exclusively for all my document and book reading needs.

There are several improvements I could wish for, but mostly I am very happy.

However, when this latest version updated my previous version, I lost my whole library of ~300 books and documents, some of which I had not transferred yet (because ShuBook mkes that a little bit awkward and time consuming).

Is there a way for me to get them back?

surfviper about ShuBook SE