Unusual offering of the inner circuit parts of the newer docks. 1.67 amps is the spec for the new, backward compatible docks. Whether the power brick also has to be changed is not clear. The 1.67 amps is just a capacity, so higher capacity ought not to matter. A different voltage, like 22v vs 24v, might matter, it would have to be tested. It depends on how the system works which is not fully documented.
It is pretty clear that a newer model Neato XV cannot be charged with the old original docks. Company reps said so. The question came up when users wanted extra docks to position in the house. The new docks have been in use for several years now -- the XV model is long superseded by the Botvac series, now in yet a newer generation with Botvac Connected.