I literally just integrated MathJax v3 with Hugo last night for my blog (abstractnonsense.xyz) so I can write some maths posts, and v4 is released today ...

Keen to try it out! I'm hoping it improves rendering - I was seeing some issues with SVG output for inline maths in Safari.

KaTeX is neat and fast, but alas the quality of the typesetting is really sub-par compared to MathJax.