Just like iOS 11, Apple is delaying a key feature of iOS 12: Group FaceTime
Apple released the seventh beta build of iOS 12 today. The update is focused on performance improvements on older devices—a tentpole promise of iOS 12—but the beta release notes reveal something unexpected about the public release of iOS 12 later this year: the Group FaceTime feature won't make the cut.
Demonstrated prominently in Apple's WWDC keynote event earlier this year, Group FaceTime would allow more than two people to participate in a FaceTime video call at once, with a presentation similar to that of longtime conference-call staple Google Hangouts. Apple has said Group FaceTime will support up to 32 simultaneous participants and that it will be supported on both macOS and iOS.
Apple's iOS 12 beta 7 release notes (PDF) note the removal of Group FaceTime from the beta (and from the eventual public release) with the following: