I see that Yoast has updated that article now but the web doesn’t lie (often) http://web.archive.org/web/20170707175350/https://yoast.com/why-we-dont-support-old-wordpress-versions/. Neither does the source code as per image below.
I’m having issues with Yoast Premium on a WP4.9.9 site and was intending to get in touch with support but realise there’s no point now. I’ll just roll back to an earlier version of Yoast that I know works with 4.9.9.
But I’m struggling with the concept of moving to Rank Math. I’m no fan of Yoast at all but things like this don’t impress me much either.
Plus, I’ve had two spam emails from the developer of Rank Math asking me to leave a review on Product Hunt – and I don’t even use it and never have!
So I’m afraid I’ll need a lot of convincing before even considering Rank Math.
If there’s anyone brave enough – and clever enough – to fork Yoast, that would do nicely.