I think I know specifically what my problem is, and it may not be solvable, but I'm hoping someone might have a simple solution.
Earlier in 2019, my Kobo Aura (circa 2013) couldn't open library books I borrowed via OverDrive even though I had authorised my computer and Kobo with my Adobe ID and I had successfully opened library epubs before. Perplexed, I tried asking Kobo customer service, which didn't help. Eventually, I connected with someone from OverDrive support who walked me through many repetitive steps and concluded that due to the age of my Kobo, it could only recognize the ADE authorization from my Adobe ID if I used ADE 3.0 to transfer the epub. I was also informed that there were no known workarounds should I ever update ADE beyond version 3.0. The problem now is that my computer updated to MacOS Catalina, and ADE 3.0 doesn't work with Catalina, so I have to use ADE 4.5 which means I can't read library ebooks any more.
Does anyone working on Digital Editions read this forum and is it possible to fix this issue so that older eReaders like my Kobo will not run into this issue? Forced digital obsolescence like this is so sad.
Alternatively, does anyone have a similar issue and have you manage to find a workaround besides accessing a different computer?