Microsoft has made its firmware and driver update schedule for Surface devices public. It shows how long each individual product still has in terms of official support. Some, such as the RT ot Pro 2, have already seen this end-of-service date come and go.
Others are yet to see the next upcoming date for their obsolescence. This is November 13, 2021, on which the Surface Pro 3 to Pro 5/2017 will cease to receive updates. This means that the 3 will get a total of 7 years of support. This is slightly confusing, as its immediate successor, the 4, also ends its life cycle on the same date, as does the first-gen Surface Book.
Howver, most devices on the list get a more constant 4 years of updates. They include the Surface Pro 6 and 7; the Go 1 and 2; the Laptops 2 to 3 and the Pro X. Microsoft has stated that it has posted this information in response to feedback from customers who want to plan upgrades for their devices in accordance with the new list.