Hi,

To determine what firmware is on the speakers, you may need to re-type them so they are Master speakers (in order to respond to MSR remote signals).

To do this, press and hold down '6' on the remote whilst turning the speaker on at the mains. That will set the speaker to Type 6.
You then need to set it to Left or Right and Master or Slave - for this purpose set each to Master (so that each speaker responds to the MSR)

When the speaker is in standby, press display on the remote, which should then flash up the firmware loaded on each speaker on the speaker's display.

To update the firmware, you'll need a Windows computer with the Meridian Flash Upload program, a NULL Modem cable, a suitable USB to Serial converter, AND the appropriate firmware.
Note there are two types of firmware - one for 7-segment displays and one for dot-matrix displays - MAKE SURE YOU HAVE THE CORRECT ONE!
Please search the forums for the recommended USB to Serial converter (not all work!) - I still have an old laptop with a proper serial port that I use for firmware updates...

Run the Meridian Flash Upload program, select the appropriate COM port, navigate to the firmware, and then click start. The speaker should say something like Downloading... and the firmware will load.

Once you have successfully updated each speaker, then you'll need to re-type them back to however you need to use them (refer to the manual) and you'll be all set.

Hope that helps.

Cheers,

Steve

Main: 861v6 (LPS), 808v6, UHD722, DSP8000SE Anniversaries, DSP5200.2HC, DSP7200.2, SW1600, Sky Q, Cambridge Audio BD, Roon, M80
Office: 861v4 (LPS), 818v3, 800v4, HD621, M&K S150P, DSP5500HC, M&K MPS2810 sub x2
Son's system: 861v4, HD621, DSP6000.2, DSP5200HC, DSP33
Spare: MCD, 100 Series, 200 Series, 500 Series, F80s, C15s.