My iPhone is currently in for repair for a few days. I’ve been using an old iPhone 8 I have lying around in the meantime, but the ultra isn’t able to pair as the phone can’t have ios17. As my main phone is having a whole new rear system and I can’t pair it with my spare I was full expecting to loose my activity data for the period while my phone is in for repair.

To my surprise, after a few days, my activity data has suddenly updated after charging the watch this morning. Checking health on my iPad and everything has synced - activity rings, workouts - everything is there except sleep. Activities have even ended up on strava (presumably via the iPhone 8 unless some sort of witchcraft has gone down)

It’s gone against everything I had read beforehand, where I honestly believed that I would most likely loose all my data and have to repair with the phone once I got it back. I’m posting this mostly to figure out how this has happened - if its a new feature in watch os10 or something - but also so those in a similar situation with a phone in for repair know this is possible because everything I had read suggested not!