It's very rare that there are any updates at all within the same generation. Year in model designation is just "ha, look at his looser driving last year BMW" and to show when car left assembly line.
There are some examples where the same generation had a significant upgrade without a facelift, but those are rare. One example I could think of is MX-5 (ND): between 2015 and 2018 there were no changes at all, but in late 2019 there was nearly complete overhaul of its powertrain and then a small update in 2021.
Everyone can tell the age of every car [1] simply by the license plate (used to be in 1 year increments, since the early 2000s it's been in 6 month increments).
[1]: Yes, yes, before some is pedantic, imported cars don't come under this scheme, and self-assembled cars also have a unique form that mean you can't tell their age.