8.0 which was released in 2012 is no longer supported, with the last updates landing in early 2016. [1]
8.1 on the other hand _is_ supported until 2023. [2]
The majority of 8.0 users immediately upgraded to 8.1 (because 8.0 was slightly terrible), so you're mostly correct. 10 years of support is pretty standard for Windows releases.