How to announce something to the users in all running conferences?

Dear all,

I know the configuration option “noticeMessage”. I really like this but the problem of noticeMessage is, that this will only work for new users and not for current Jitsi sessions.

What I am looking for is, that I could push a message on the web or into the chat like “Server maintenance will start in 30 minutes”. This message should displayed in all conferences.

Is this possible?

There is no such feature at the moment.
But this sounds like a custom prosody module. From there you can see all conferences and can broadcast a message to those.