User blog comment:Master Sima Yi/Assassinews 03-12-'14 — New Assassin's Creed in Victorian London leaked/@comment-3046679-20141213185646/@comment-13471981-20141213185921

I think the crouch mode can be toggled, Kain (at least on PS4). I didn't realize this until a while into the game either, but you don't have to hold whatever button to have Arno crouch continually. On PS4 that's L2, and toggling it is far more responsive than holding it down :)

But yeah, I miss whistling especially.