(news and commentary)
Along with the D7100 Nikon introduced another wireless remote control, the WR-1 transceiver. Now we know why the one launched with the D5200 was called the WR-R10 ;~).
Let's back up: the WR-R10/WR-T10 remote controls were a step up from the infrared wireless remotes Nikon has been using and continues to support in the consumer lineup. It used radio communication and added essentially a function button to the remote controller process. The new WR-1 is like an WR-10 combo on steroids: you can enable and verify multiple settings remotely, and you can have one WR-1 communicate to many WR-1's acting as receivers, supporting things like simultaneous and synchronous releases. Communication can be as far as almost 400 feet, and up to 15 different channels are supported (gee, that's just enough for my workshops to function ;~). No price yet, but it too will ship in March.
As with the D7100, I'm still collecting information and getting questions answered about the WR-1, so I'm sure I'll have more to say when I have additional details.