I received a report that the Nikon WR-A10 wireless remote adapter is discontinued (or it will be discontinued soon). In the US the WR-A10 is currently in stock at B&H (out of stock at Adorama and Amazon). Here is the report I received:
Some 4 months ago I ordered from a local Nikon supplier in Australia a replacement WR-A10 Remote Control for my D500 and D850. I have just received a phone call from the supplier that they have been advised by Nikon Australia that the WR-A10 Remote Control has been withdrawn from manufacturing and is no longer available. This effectively means I can no longer trigger and control my Nikon SB5000 by remote radio control from my cameras.