Tesla CEO Elon Musk said in an email (via Tesmanian) to his employees that "It's time to go all out and bring the Tesla Semi to volume production." No timetable was provided, but just a few months ago the California-based electric car producer said in an investor call, "We are shifting our first Tesla Semi deliveries to 2021." Considering that it's already June of 2020, we'd say it's definitely "time to go all out" if Musk plans to stick to his 2021 customer delivery target.
Musk also said in the email that the Semi's battery and powertrain will be produced at Tesla's Gigafactory in Nevada but that the rest of the commercial vehicle's production would happen "in other states." It's not clear if Tesla's production facility in Fremont, California, would be in the mix for Semi assembly, especially considering how publicly upset Musk has been with local authorities in Alameda County where the factory is located. Musk has said on Twitter that he intends to move Tesla out of California and into the open arms of Texas or Nevada, but there wouldn't seem to be enough time to make such a move ahead of the Semi's impending production.
Tesla unveiled its sleek Semi at an event in California way back in 2017. At the time, the automaker said it planned to begin production of the truck in 2019, but that's obviously been pushed back (several times). It's not yet clear how the truck's design or specifications may have changed over the past few years. Musk's email suggests the Semi's "limited production" status (we're not quite sure what that means, honestly) has allowed Tesla engineers to "improve many aspects of the design." We look forward to seeing the finally finished product.