Tesla's original family passenger vehicle, the Tesla Model S, hasn't had a serious overhaul since the 2016 model year. That's when it received a restyled front fascia without the black faux-grille panel and began picking up new features like Autopilot 2.0 with Enhanced Summon, and later, Sentry Mode.

But recently, a number of observers have picked up on indications that a new overhaul could be coming to Tesla's flagship Model S sedan and Model X crossover soon. Now, we can add one more item to the evidence list: some lines of code within Tesla's latest software update pertaining to a cabin-facing "selfie" camera in the interior.

A "selfie" cam is already included on the Tesla Model 3 and Model Y, but so far, it has yet to appear in the S and X. The camera will take a central role in Tesla's planned autonomous robotaxi fleet, keeping an eye on ride customers and making sure that they don't misuse or vandalize the car while no driver is present.

A well-known Tesla hacker who goes by the name of "green" on Twitter found the software code, which refers to something called "S/X P2" that reportedly includes the selfie cam with Autopilot hardware version 3.2.

The new software code, in conjunction with the fact that Tesla recently extended its holiday shutdown in the US and increased pricing for the Model S and Model X in Europe, highlights the possibility that the flagship models could be refreshed very soon. In fact, Tesla had a cabin refresh for both models planned for last summer, but the project was sidelined as the electric carmaker devoted its resources to ramping up Model 3 production and launching the Model Y.

With the Model Y out and Model 3 production now in full swing, 2021 seems like the year for a significant Model S/X update.