After installing the 12.1 beta, the iOS Simulator in Xcode appears to offer support for virtualized 4K external displays, according to developer Steven Troughton-Smith.

That's not a feature that's possible with existing iOS devices using a Lightning to HDMI adapter, which suggests it could be a new option targeted at upcoming iPad Pro models that are rumored to be getting USB-C ports instead of Lightning ports.

New in iOS 12.1: the iOS Simulator supports virtualized 4K external displays. This is not possible on any existing iOS device via the Lightning HDMI adapter — lends credence to iPad perhaps getting a USB-C port for 4K video-out? pic.twitter.com/WfNBerHIrb — Steve Troughton-Smith (@stroughtonsmith) September 19, 2018

According to well-respected Apple analyst Ming-Chi Kuo, who is well-connected to the Apple supply chain, Apple is planning to replace the Lightning port on the upcoming iPad Pro models with a new USB-C interface

Apple has been transitioning to USB-C in its Mac lineup since 2016, but despite a rumor here and there, has not adopted USB-C ports for any devices in its mobile lineup. An iPad Pro with USB-C would bridge the gap between the Mac and the iPad, making Apple's pro-level tablet even more viable as a computer replacement.

Kuo believes the USB-C iPad Pro models will ship with an 18W power adapter with a USB-C port, which would enable faster charging.

We may not have to wait long for Apple to unveil new iPad Pro models. There are new iPad Pros and Macs in the works for fall, and in years when Apple has a lot of fall devices to unveil, it's held two events, one in September and one in October.

For that reason, we could soon hear news of an October event where new iPad Pro models and new Macs will be introduced.

Along with a USB-C port, new iPad Pro models are expected to have edge-to-edge LCD displays with a TrueDepth camera system for Face ID and no Home button.

Additional details on the upcoming iPad Pro models can be found in our iPad Pro roundup.