We have identified a few issues with iOS 16 with Cisco Umbrella. Cisco Security Connector users may experience SMS/MMS message failures. Users without an app (e.g. 220.127.116.11 set as DNS resolver) may experience DNS timeouts. We recommend that Cisco Umbrella customers stay on iOS 15 until further notice. Cisco Umbrella and Apple engineers are working on this issue. Once we have a workaround or permanent fix we will update this notice.
This issue has been fixed in the iOS 16.2 release.