My cards are:
IE16 (digital in)
OA00U (analog out 22bit 48Khz)
OA00U
OE12 (digital out)
COO (COMM)

I got my responses by looking at the 861 2.5 firmware release notes.

Quote
Hardware restrictions (card needed and feature of the 2.5 software)

IE16 :
MHR input from 800.
Any 96kHz processing or output.
Upsampling of 44.1 or 48kHz sources
(and possibly from my 596P)

Quote
OE12 :
OE12 is required for MHR output, or
96k output if DSP Loudspeakers are used
(looks like my DSP3100 will have that feature)

Quote
New software highlights :
Support for new MSR3 and Meridian 800 DVD/CD Machine.
4-channel 96/24 MHR output in Trifield, Music, Stereo & Direct.
Upsampling for 4-channel output from 44.1kHz and 48kHz sources.
Room correction with graphical set up.
New MLP software.
Mono DSP Preset adds a �Party� option (mono from all channels).
Sine-sweep for setting up Room Correction and room acoustic checks.
Start-up volume level.
(So my wish about upsampling may be fulfilled!)

The seller told me that he couldn't distinguish his v2 from his v6 when using his DSP8K.

I can't wait!

861v2, DSP3100, DSP3100HC