To add my voice to M on this point - I too would like to see and be willing to pay (with in limits) for an upgrade for both HT & music for the 861v8.

Somewhat off topic - I have used M gear for over a decade now and have not really looked at other manufacturers offerings. Today I had a quick look at Theta Digital site and they are still at HDMI 1.4a and decode more (albeit accepting their mixed audio & video signal solution) with the Casablanca IIIHD / IV.

Other than the Japanese, which high end producers are now offering HDMI 2.1 and DD Atmos/DTS X? Anthem MRX 1120 (only HDMI 2.0)?

Z0: 861v8+ID41+Roon on a QNAP, Naim NAP300, Sonus Faber Amati Anniversario

Z1: Arcam AVR-450, Oppo BDP-103D, SkyQ, Apple TV, Kuro KRP-600A, Sonus Faber Guarneri Memento & Cremona Center M speakers, Martin Logan Descent-i Sub, 2 B&W wall speakers

Z2-6: Roon controlling MC600 Zones into Parasound amps to B&W ceiling speakers