Why be-and-lo-hold @JBTexas, it is so! My Gen3 is also now on iro3-firmware-hk-5-645, possibly updating itself since plugging it back in recently after its winter nap. I just got my system running again, reinstalling the booster pump I overwinter in the garage, resetting the backflow valves, turning the water on at the meter, and testing each zone. All was working though I do need to move a few heads and replace a couple. I’m excited that HomeKit may actually work. We have two iPhone13mini’s both on v17.4 of iOS.
On a related note, other than possibly HomeKit working, is there any other noticeable difference between -645 and earlier firmware that anyone has found?