Alloy currently creates TabbedGroup from Ti.UI.iOS only. This needs to change to create it from Ti.UI instead when building with Titanium 8.0.0 and higher.
We're adding Ti.UI.TabbedBar support to Android in Titanium 8.0.0 for parity with iOS. See:
iOS currently has it defined under both Ti.UI and Ti.UI.iOS. In Titanium 7.x.x, Ti.UI.TabbedGroup is flagged deprecated, but we plan on reversing that and making Ti.UI.iOS.TabbedGroup deprecated in 8.0.0. See:
This should probably be implemented similar to how it was done for NavigationWindow here...