In order to migrate my library from my old PC, the first thing I did was to install Digital Editions version 1.7.2 on my new PC. I couldn't install version 3 right away because then I'd lose thousands of annotations. I have to figure out what additional steps are needed to complete the migration and in what order.
I will copy all files in the \My Digital Editions directory from the old PC to the new PC. I also have to be sure the new PC can find my PDF files and notes in the directories on my new PC. This requires editing the MANIFEST XML file to change the PDF directory locations. I hope that's the only XML editing I need to do, since I don't know XML.
I understand from another user (sjpt) that I may need to "deregister ADE on the new machine (ctrl-shift-D) and then reregister it." That may be due to Digital Rights Management. So I will activate my new computer with Digital Editions using an ID. I expect to do that step last, since I have just a few books with DRM.
I plan to perform these steps in the order I've described them. I think I've identified all the steps needed to get Digital Editions 1.7.2 working. I'd welcome advice from other users who have experience in migrating their libraries. Thanks
P.S. Documentation on Digital Editions seems pretty minimal, so I'm wondering if Adobe is phasing out the product.