Newer Tesla Model S and Model X owners get a big benefit vs. their predecessors – all the sensors and computing power onboard needed to achieve full self-driving when the software’s ready. But they also had to deal with a temporary inconvenience, since they shipped without the majority of Tesla’s current Autopilot features, which provides advanced semi-autonomous driving for use on highways, including automated steering for lane-keeping, and adaptive speed for maintaining distance with other cars. Tesla CEO Elon Musk says that owners of so-called “Hardware 2” Tesla vehicles won’t have to wait long to get their functioning Autopilot update, however.

Looks like we might be ready to rollout most of Autopilot functionality for HW2 towards the end of next week — Elon Musk (@elonmusk) December 23, 2016

The update has required additional time because it’s actually different from the original Autopilot system, and takes advantage of new on-board computer vision capabilities made possible by the changes to the sensor and computer hardware.

Musk notes that “most of” the original Autopilot functionality will be pushed via this update, but he doesn’t specify exactly what. The major features still not present in HW2 vehicles include emergency braking, blind spot detection, smart cruise control, auto steer and auto lane change, but other features also still need to be added to reach parity.

Again, owners of the newer Tesla hardware stand to benefit in the long run – only their cars will eventually be able to drive fully autonomously, after all, and in the meantime Autopilot improvements that aren’t possible using the old sensor loadout and computing stack will probably make it to their vehicles, too. But those in possession of the new cars are probably happy that Tesla appears to be on track to deliver an end-of-2016 treat with the addition of some of these highlight features.