Oh dear! I totally forgot he asked this yesterday. My post was intended to be a general bug report. I don't know when that sound was introduced for online user, but my bug report was for this new feature in elten 2.4.3 where you can be notified if a certain user comes online if you so desire.
Maybe it's something with the addon on the computer in question, because it used to work and it's still working on my Windows 11 machine. I may try reinstalling the addon, and if that doesn't work, I'll have to reinstall Elten I guess. But I want to get round that.
You need to activate it first, and of course, you need to know how markdown works. For example, one or two number signs for heading level 1 or 2 respectively, * for list items, that's what I seem to recall.
Isn't there a checkbox in a thread to enable markdown for a certain post if you've got the Courier package? And I think there need to be spaces after the number signs.