Every Model S produced from September 2014 onward included the Autopilot hardware, and it was officially released in October 2015 as a software update.
Event text from Wikipedia: “Tesla Model S” (linked citation above)
More than 20,000 Model Xs had been reserved by September 2014.
Event text from Wikipedia: “Tesla Model X” (linked citation above)
Vehicles manufactured after September 2014 included Hardware 1 (HW1), which supported Autopilot.
Event text from Wikipedia: “Tesla Autopilot” (linked citation above)
Groundbreaking for the project occurred in September 2014 with a target completion date of early 2016.
Event text from Wikipedia: “SolarCity” (linked citation above)
UC San Diego installed this system, which has 5 megawatt-hour (MWh) capacity—enough to power 2,500 homes—in September 2014.
Event text from Wikipedia: “Tesla Powerpack” (linked citation above)