The HDMI version is indeed important, and the 2.0 version is soon outdated.
8K video is soon on its way, like it or not. HDMI 2.1 will allow faster refresh rates so as to allow 8K resolution video at 60 frames per second and 4K at 120 frames per second. In other words, HDMI 2.0 is not at all adequate for running such higher resolutions.
Were I to update my receiver, so as to be at least be a little prepared for the arrival of 8k with HDR, I'd wait for one with a minimum of HDMI 2.1 ports. 8K @ 120 fps and HDR with Dolby standards...now that's being a bit future proof for the coming video models. As you may be aware, 8K will be making its appearance in Japan...2019. Even though it will take longer to have broadcasting at that resolution, it will still be very valuable for graphic artists.