Latest as in the last ~10 years worth of releases. They are on gen 12 or 13 (I had or still have gen 5, 6, 8, 11).
The worst problem is they are Intel-only so I moved to T14s which is not as polished (their premium AMD option is too MacBook-like with sharp edges and worse keyboard in Z13 or something), yet AMD is much closer to Macs on thermals, battery life and performance.
Ah, that is an excellent improvement!