Code in the iOS 12.1 beta released this morning suggests Face ID has built-in support for landscape orientation, according to information shared by developer Steven Troughton-Smith.

A rendering of the upcoming iPad Pro said to be based on leaked CAD drawings

According to Troughton-Smith, landscape support for Face ID has likely been built into the update for upcoming iPad Pro models that are expected to offer Face ID.

Face ID has support for landscape orientation (presumably for iPad only), and iOS 12.1 seems to care a lot more about whether an external display is connected (perhaps due to iPad USB-C rumors; it won't have the Lighting HDMI adapter as an intermediary for video-out) — Steve Troughton-Smith (@stroughtonsmith) September 18, 2018

Troughton-Smith says that landscape Face ID requires a different alignment for the front-facing sensors of the TrueDepth camera system, which is why it won't be available for iPhone models that have Face ID.

From what I gather, landscape Face ID would require a realignment of the front-facing sensors, so you won't see it on existing hardware https://t.co/gVyB4Hz3pW — Steve Troughton-Smith (@stroughtonsmith) September 18, 2018

Previous iPad rumors have also suggested Apple would introduce Face ID support for landscape orientation specifically for the new iPad Pro models, because being able to unlock only in portrait mode would be inconvenient with a larger tablet form factor that's most often used in a horizontal orientation.

Right now, Face ID on the iPhone X and the new iPhone XS and XS Max devices works only in portrait mode, with the devices unable to recognize a face when held in landscape mode.

There has been some confusion over how Apple will implement Face ID in the iPad Pro models, though, as some rumors have pointed towards the inclusion of a new mystery port that's supposedly a Smart Connector located at the back of the device in leaked cases and CAD drawings.

A rendering of the upcoming iPad Pro said to be based on leaked CAD drawings

According to Japanese site Mac Otakara , which has somewhat of a mixed track record when it comes to rumors, the Smart Connector allegedly works with a new vertically oriented Smart Keyboard. Mac Otakara believes Face ID in the iPad Pro will work only in vertical orientation, but both today's information and prior hints of horizontal Face ID support suggest that's inaccurate.

Troughton-Smith shared a few other tidbits he found in the beta. There appears to be code to support an upcoming change to MFi game controllers that will offer up compatibility with clickable thumb sticks, and iOS 12.1 "seems to care a lot more about whether an external display is connected," which could be related to rumors of a switch from Lightning to USB-C.

Apple's iPad Pro models are rumored to feature edge-to-edge displays with no Home button, no headphone jack, and a USB-C port instead of a Lightning port. We're expecting Apple to introduce the new iPad Pros before the end of the year, perhaps at an upcoming event in October.