“Re-engineered” PH04

I recently purchased a PH04 as this appeared to be the most current model. However, I have not been able to find any info at all as to what has been updated. In fact there seems to be very little information in general about the technology in the PH series. It’s surprising given these are some of the most expensive products you can get from dyson. Does anyone out there have any insight as to what was changed for the PH03 and 04?

(Edited by moderator – tags added)