While syncing the overall tracking database is a tricky one without a central server (because a core design value for Foreground is not sending all your data to someone else), it would be a lot easier to sync your Exist attributes from multiple Foreground clients by making Exist have a server-side integration for Foreground so it can handle multiple Foreground clients and sum all the totals across them. I think this would solve the issue for many folks and as it’s much more viable than the full sync, I think as a compromise it’s worth doing.