Apple has released the fourth iOS 12.1 beta to developers. The company also released tvOS 12.1 beta 4 and watchOS 5.1 beta 4.

Build numbers for these versions are as follows:

  • iOS 12.1 beta 4: 16B5084a
  • tvOS 12.1 beta 4: 16J5600a
  • watchOS 5.1 beta 4: 16R5584a

First introduced in September, iOS 12.1 offers Group FaceTime, plus software for Dual SIM support for the iPhone XS, iPhone XS Max, and upcoming iPhone XR.

We’ll add more information about these developer beta as it becomes available.