I'm against html5 for quite a variety of reasons, one of them is that isn't an standard (or "living standard" as WHATWG says) but an eternal draft. 
Which only Google Chrome (spyware browser) can fully implement , leaving all other minor web browsers behind. 

And the second is that while it exists, it harms the WWW as we know it , along with , say , JavaScript (websites are heavily infested with this nowadays) , and thus they render useless without it. 

I use a modified variant of Luakit1 which is a browser configurable and extensible by Lua, it fits all of my needs, although if I actually browse for example , the ActivityPub social media platforms I have to use Falkon[2] because it crashes Luakit , also most of them require JavaScript enabled for them to work , and I just can't be bothered in whitelisting sites in the browser. 

Back to the point , legitimately HTML 4.01 was the latest version of HTML itself , not HTML5. 
I use XHTML 1.1 on my personal website because I want it to work on literally any web browser , even the corporate ones , without issues. 
I just can't do that with HTML5 , because as mentioned before, it only gets fully implemented in Chrome.

EDIT : Apparently not even Chrome even can implement fully its own thing , lol3

The web as we know it may be just dead , or who knows?

1: <https://luakit.github.io>
1.5: <https://gt.kalli.st/novaburst/luakit-misc>
2: <https://www.falkon.org>
3: <https://digdeeper.neocities.org/images/html5test_scores.png>

=> http://nothings.org/writing/websucks.html Why the Web Sucks (You Just Don't Know It)
=> https://kill-9.xyz/harmful/software/html5 HTML5 (and only 5) considered harmful
=> https://www.nuegia.net/articles/open%20letter%20to%20webmasters.txt Open letter to webmasters
=> https://againstmodernbrowsers.neocities.org/ Against Modern Browsers
=> https://drewdevault.com/2020/08/13/Web-browsers-need-to-stop.html Web browsers need to stop

* Update #1: I'm no longer using Falkon as secondary browser