Shortly after the release of the developer beta 3 of high sierra, developers also got a iTunes 12.7 beta. But I don't think public beta testers got this yet despite already getting public beta 2 of high sierra. The reason may be because of the bug where ios devices are not showing up once plugged in. They may release an itunes 12.7 beta to public beta testers in the future however and it will be interesting to see if they get the bug. --- Post Merged, Jul 12, 2017 --- And the following advice may be a bit too late for developers this time, but if public beta testers get the itunes beta at some later stage, here's what I did when I installed the high sierra developer beta 3 and itunes 12.7 beta: 1. I DIDN'T install them together as many developers may have done. 2. I installed the high sierra beta 3 separately first. 3. Then I did a time machine backup (now that time machine is fixed) 4. Then I installed the iTunes 12.7 beta. 5. Then I did another time machine backup. This lets me downgrade itunes to 12.6.1 if need be, but keep the high sierra developer beta 3.