I’ve had ReadMe! for years - since before you had to pay for it. It’s still just a basic reading app. I got it because I wanted to try Spritz - which itself has issues. Even after years of availability, the library STILL cannot be sorted. If you are an avid reader as I am, you have thousands of books. Imagine trying to find a particular book. Now imagine remembering the book but not remembering the author’s name or the book title. You have to sort through thousands of titles until you maybe see something that reminds which book you’re thinking of.
The developer should have provided us with sorting capability YEARS ago - sort by title, sort by author, sort by category.... and that’s another issue. There is no way to categorize your books. The bookshelf should have been able to have categories assigned - fiction, non-fiction, young adult fiction, children’s fiction (where the books I write listed), science fiction, non-fiction biographies, non-fiction autobiographies, history - you get the picture.
This is still just a basic app with limited capability. At least Apple’s iBooks gives you the ability to create categories to put your books under. Perhaps the developers should look at iBooks and Marvin for examples of what a reader should be able to do....