Do you need to know in detail the last papers of your future PI in preparation for a postdoc interview?
The advice &quot;look at the latest...&quot; is good advice. Whether it is necessary to do depends entirely on the views of the PI. They may care deeply, or not at all. Certainly it is better to be as prepared as possible, even if their main concerns are elsewhere.
If the position is competitive, then it is likely that other candidates will be as prepared as they can. Due diligence, I guess.
Even if you only bring questions about those papers to the interview you will be better off than being completely unprepared.