My laptop needs Adobe Digital Editions 3.0 for my Pocketbook PB632

I used to be able to download and read library books directly on my pocketbook pb632 using the Libby app. Now I have to use Borrowbox and download the book on to the computer first and transfer it to my e-reader. This is not working and the pocketbook support say that I must use Adobe Digital Editions 3.0. I don't know how to find 3.0 and the chat assistant said that she could not help with such questions and referred me to you.