I moved all my V1 devices from a C5 to a C7 late last year, around Sept I think. This post describes what I had to do. I was able to get all my V1 devices re-connected. It was not an easy task then, it was a bit frustrating, but I did get them all connected. Much easier when I first connected them several years ago. If any recent updates have made it worse you may be out of luck.
As mentioned by @StephenH , I want to retire all the V1 devices I am trying to buy replacements a little at a time. So far though they all still work and work well. I hate to lose them as battery life on these old V1 devices is some of the best of any devices I have ever owned.
