Apple initially discussed group FaceTime during WWDC in June, where it detailed all of the new features coming to iOS 12. Group FaceTime allows up to 32 people to video chat at the same time. It also includes support for Apple's Animoji, so users can chat with different digital masks on their faces.
Group FaceTime was one of the few major feature updates in iOS 12, which was otherwise devoted to incremental nuts-and-bolts updates such as faster performance.
While it has been available to test in some of the earlier development versions of the software, Apple has apparently decided it isn't ready for everyone to use.
A similar situation occurred when Apple first announced AirPlay 2, Apple's new wireless streaming technology. AirPlay 2 was supposed to launch in last year's iOS 11 but didn't launch until June of this year.
"Group FaceTime has been removed from the initial release of iOS 12 and will ship in a future software update later this fall," Apple said in its latest developer release of the software.
Apple typically launches the new versions of iOS in September in tandem with the introduction of new iPhone models.