For web sockets? No.
You either run something like Node (which I don’t see mentioned there), or something like Ratchet (which I strongly doubt your hosting plan would be happy about, it’s essentially a super-long-lived PHP script). Web sockets are just not how PHP works - PHP is all about “receive a request, respond, close the connection” rather than leaving the connection open. I’m not quite clear what they’re calling a simultaneous connection but if that’s 200 concurrent connections, you instantly limit your site - because every active user would hold one of those connections open with a web socket, meaning every other request would have to share what’s left.
Or you don’t use web sockets and have every user on the site phone home every couple of seconds. (XF does some element of this for drafts, but not nearly at the frequency that makes sense) Which means an instant scaling of traffic just to get this indicator.