The latest discovery in the iOS 12.1 beta is that the software appears to support 4K external displays — something impossible on any current iOS device, even when using Apple's HDMI adapter.

This may support the idea that upcoming iPad Pros will offer USB-C, developer Steve Troughton-Smith suggested on Twitter. A virtualized 4K option appears when running Apple's iOS Simulator, used to test out iPhone and iPad apps.

Apple is widely expected to introduce new iPad Pros this fall, possibly in October. Specifically the company should deliver updated 10.5- and 12.9-inch models with faster processors, edge-to-edge LCDs, and Face ID. This is supported by other code strings in iOS 12.1, including one for Face ID in landscape mode, and another labelled "iPad2018Fall."

Less certain though is whether the tablets might support USB-C, whether replacing or in addition to Lightning. The former may be unlikely, since it would be inconsistent with Apple's latest iPhones while simultaneously demanding a new collection of accessories.