S        This expression returns the welcome message (similar to Message of the Day) sent with the connect approval message that triggers the On connect condition.

It will stay unchanged until disconnection.


In Relay, due to a bug the last welcome message will stay beyond disconnect; and the length of the welcome message is limited to 512 ANSI characters; even if more are sent, only 512 will be returned by the expression.

In Blue, it is unlimited in length, and expected to be Unicode.