Every HW 2.0 or later car should still have the foundations for self-driving functionality, in other words. And while it's "highly unlikely" that these vehicles will need an upgrade when fully autonomy is an option, Tesla will upgrade them to 2.5 for free.

The improvement underscores the fine line Tesla has to walk with when it comes to upgrades. The electric car maker revolves around constant iteration, but it also has to meet the expectations of customers who bought expensive add-ons assuming they'd eventually get full self-driving features. Tesla likely has more headroom for vehicle upgrades than this, but it can't do anything that would limit driverless tech to post-2.0 vehicles.