Just had a situation where a newly installed Unifi U7 Pro was plugged into the PoE port on a UDR, it worked but showed a warning message in the Unifi UI (See following quote and the image below)

The access point is connected to a port, which does not supply sufficient power for optimal operation. To ensure reliable and full-capacity performance, please connect the access point to a PoE+ compliant port.

So I checked my UDM and found both UDM's and UDR Unifi Routers don't have PoE+

There are different classes and types:

Class 2: Type1 PD, it can draw a maximum of 6.49W.

802.3af Class 3: Type1 PD, it can draw a maximum of 13W.

802.3at Class 4: Type2 PD, it can draw a maximum of 25.5W. <= this is PoE+

So the work-a-round was to move the U7 Pro to be powered off a Aruba 1830 which has PoE+ Class 4 Type 2 capabilities. It stopped complaining after I did that.

The Unifi UDR supports LACP so I created a LACP Trunk on port 4 to go to the Unifi U7 Pro and I use another trunk to go from the Aruba to the Unifi UDR on port 8