One of the more common questions we've been getting here at iDB since the release of the Yalu jailbreak for iOS 10 is when AppSync Unified, from Karen Tsai (angelXwind), would be getting an update to make it compatible with the new jailbreak.
As you may be aware, many people got themselves into a respring loop of some description by installing AppSync soon after the Yalu jailbreaks came out. That should now have been fixed with this new beta version of AppSync Unified, available on Karen's Cydia repository.