It's going to need to be more than a processor upgrade. At the very least, it will need the ability to decode Atmos and then several more channel of output, likely 16 if it wants to represent. If they provide analog support, it's a crowded back panel, assuming the commensurate # of speakerlink connections. Should be interesting. Some have suggested processing is done at the HD621 level, which should assume a considerable upgrade there.

Primary: MD600, MS200 (SpeakerLink to AES), Trinnov ST-2, Ayre V6-xe, Salk SS8 3x LRC.
Secondary: MC600 (whole house).
Zone one: 568.2, G57, MS200, Spatial Hologram M2SE.
Zone 2-6 (Awaiting assignment).