Correction: This article initially referred to the new Tesla software update as “8.1,” based on statements from CEO Elon Musk. Tesla has clarified that this is an incremental upgrade with no version designation.
On Saturday, Tesla Motors CEO Elon Musk announced that a major new software update was being sent to a small number of newer Tesla vehicles, with more ideally updated over the coming week. The update will include upgrades to the cars’ Autopilot feature.
HW2 Autopilot software uploading to 1000 cars this eve. Will then hold to verify no field issues and upload to rest of fleet next week.
— Elon Musk (@elonmusk) December 31, 2016
Get Data Sheet, Fortune’s technology newsletter.
This update is specific to vehicles with the enhanced hardware package that Tesla made standard starting in October. That hardware includes more cameras, ultrasonic sensors, radar, and a much more powerful onboard computer.
But those newer vehicles didn’t initially have some of the Autopilot features beloved by owners of existing Teslas, including automatic emergency braking and lane guidance. In October, Tesla said the new system needed more validation before those features would be activated.
According to Bloomberg, the new update will enable those missing features on newer cars. But sources speaking to Elektrek claim that some of those features will be limited, with Autosteer only working when vehicles move slowly on clearly-marked highways.
The new hardware system was introduced following Tesla’s split with Israel’s Mobileye. That rift was triggered at least in part by a fatal Tesla crash in May 2016, after which Tesla was seen by some as shifting blame to Mobileye’s cameras.
What the update does not include is the full autonomy that the new generation of Teslas are built to be capable of. It’s still unclear when those capabilities might be rolled out to owners, but Musk has predicted that a Tesla would make an entirely autonomous coast-to-coast demonstration trip by the end of 2017.
