I need to upgrade an old installation of 56.0.2 (EME-free, 64-bit Windows) to modern Firefox. I'm wondering if there are any changes or known upgrading issues that might be an unpleasant surprise when jumping all those versions, or precautions I may not have considered.
I've read these already:
KB: Software Update
Firefox 57 and later: WebExtensions status of legacy add-ons
My experience preparing for the Firefox 57 add-on apocalypse
How to undo zoom changes in v103?
I will back up the profile folder, and create a system restore point. I've found adequate replacements for most add-ons. I plan to download an offline installer from here, not a stub.