https://www.cnet.com/news/hdmi-2-1-what-you-need-to-know/

Today's devices mostly use HDMI version 2.0, or one of its several iterations. It's possible well see a handful of TVs in 2019 with full or partial 2.1 implementations. How does that affect you? Not much. You can't upgrade your current TV to 2.1 spec, and there are no HDMI 2.1 sources yet. This update is quite forward-thinking and takes into account formats and resolutions that won't be widely available for years. However, if you're considering certain new TVs in 2018 and 2019, you should make sure you understand the limitations of 2.0, and what 2.1 will offer if you choose to wait on your TV purchase.

Don't like reading (much)? Allow me to fire some HDMI 2.1 bullets.