https://www.cnet.com/roadshow/news/elon-musk-tesla-autopilot-chip-upgrade-6-months/

Buyers with eligible cars who haven't yet paid for the required option will be able to do so and receive the upgrade. It bears noting that this computing-power upgrade doesn't yet enable any kind of self-driving. It merely enhances the power of the car's neural net, improving Autopilot performance and paving the way for additional features in the future.

This is in addition to Tesla's version 9.0 software upgrade, which was recently pushed to Tesla vehicles via an over-the-air update. This upgrade included an improved version of Tesla's neural net, and according to another Musk tweet, its performance improved by approximately 400 percent over the pre-9.0 neural net.