This is the tail wagging the dog. The plugins are going to be broken whether the update from 3 to 4 happens manually or automatically (and, if anything, discourages manual updating despite all the popups).
Windows has had binary compatibility for decades. Why not just version the internal browser API? (Extension XYZ was built against FireFox 3.6).
Windows has had binary compatibility for decades. Why not just version the internal browser API? (Extension XYZ was built against FireFox 3.6).