Tesla has been making tremendous strides in self-driving technology. Just last April, the electric automaker introduced "fully self-driving" technology into their newer models, the Model S, X, and 3. Now they're looking into to retrofit the technology into their older models.

CEO Elon Musk explained on Twitter that all currently produced models will be built with the processing chip needed to achieve a fully self-driving state. He expands on the idea of building "a million robotaxis by end of 2020" if Tesla was to upgrade the already released models. When asked about when they would do that, he cited the end of the fourth quarter as an estimate.

The option will be available on any Tesla vehicle with the Autopilot Hardware 2 package. Currently, new vehicles offer the technology as an upgrade for an additional $6,000. We can only imagine that the same upgrade for older models will be around the same price.

Expect more details about this toward the end of the year.