From the Webpage :
" No HDMI 2.1 receivers were officially announced at CES 2020 but Yamaha's 2020 line-up of Aventage receivers will seemingly be one of the first to arrive with HDMI 2.1. The Yamaha RX-A8 (11 channels), RX-A6 (9 channels), RX-A4 (7 channels) and RX-A2 (7 channels) were detailed in a now-removed video and summarized in German Hi Fi forum."
For those who understand German , here is a link to the German Hi Fi forum post.