Elon Musk, CEO of Tesla, has admitted that millions of owners of the company's cars will need hardware upgrades to run a future version of its Full Self-Driving software that does not require human supervision. This admission could potentially lead to legal challenges for customers who mistakenly believed their cars were one software update away from being able to drive themselves. The third version of Tesla's driver-assistance tech, "Hardware 3," will require a new computer and new cameras, and Musk said it will be so arduous that Tesla may build "micro-factories" in major metropolitan areas to reduce the burden on its service centers.