I just moved all my V1 devices from a C5 to a C7 on the latest firmware. That being said it was not a simple process.
The process took several days to work out. This is the process I used and it worked on every device I had. I paired V1 buttons, contact , motion and Smartplugs.
Reset the device, and start the pairing process on hub.
In every case it would time out. As soon as it did I would wait a beat and just click V1 inclusion again, don't do anything to the device. Just leave it in pairing mode, LED should be flashing. In most cases it would pair on the second round.
In some cases it would pair, when it actually did not. I could see that the device did not in fact pair, as it would still be flashing. In these cases remove the battery. Just give the device it created a bogus name and immediately go to device details page and remove it. Then go to your device page and make sure it didn't create other devices called device. If it did remove them as well. If you don't it will say it found an existing device and won't let you pair the device again. I saw it create as many as three devices, so refresh and check the device page a few times before you try again.
Once you have removed the bogus devices just start over. I had some devices that paired fairly easily and some that took many tries before I got them connected , but I got every device I had re-paired.
