Page 16 of the 218 used guide says IR in only relevant when used with a G12, which is a Meridian IR sensor. Taken literally it won’t do IR with any other sensor. The user guide also discusses control via IP through a SpeakerLink connection. A reviver or can allow for connection to legacy M controllers. It would seem. A control system can take it from there.

I have 2 systems with 218s, one integrated with an 861v4, the other with a G61R. Both the processors Through the v4 and with a reviver, I can control/group the 218, a MS200 on porch, and ID40 for Trifield.

Some of the detail above may be corrected by folks on here much more knowledgeable than me, but you should be able to accomplish your objective. As to Firmware, it is designed to be updated automatically, but I had to get something updated through M’s Sooloos program as I use Roon. From my TV optical out, to the 218 gets me access to sound from several HDMI sources to all three of my M endpoints.

James
NC1: 861v8, ID41, 218, 251(to outdoors), DSP8000SEUG, 7200SEC, DSP520 rears, Apple TV, DirecTV, Oppo BD103, QNAP251, Roon
NC2-M7005, Triad Silver Speakers,Acurus Amps

FL1: 861v4, ID40, 218, MS200, DSP8000SEs, DSP7200SEC, DSP5000s, DirecTv, AppleTv, OppoBD103, QNAP469, Roon
FL2: Marantz 7005, 251, M60s,60C,33s, Oppo BDP-93,MS200, Roon