Look up in the helpfile:
- the "new server window" checkbox for options:connect (there's also a hint to the rightclick-menu for the "connect"-icon)
- the -m switch for the "/server" command
- the topic "multi-server" with basic info on how to address individual/all connections in scripts
Edit: here's the relevant part of versions.txt
03/02/2002 - mIRC v6.0
176.Added Multi-Server support. mIRC now allows you to connect to
multiple servers at the same time.
This feature required major internal changes to mIRC code and
forced improvement of code in many areas which has hopefully
resulted in a more stable/robust mIRC.
Added "New server window" checkbox to connect dialog. To open
a new server window without connecting to a server, you can
check the "New Server Window" checkbox and press the OK button.
Added "New Server Window" menu item to options toolbar button
servers popup menu. You can also open a new server window by
holding down the Shift key when you select a server from the
Added multi-server dialog to connect/options dialog.
New commands and identifiers:
$cid - returns server connection id for current script
$wid - returns window id for current script
$status - returns server connection status. Also returns
"closing" during the on disconnect event if the
status window being closed is the cause of the
$activecid, and $lactivecid.
$scid(N)[.command], where N is a $cid value
$scon(N)[.command], where N is the Nth connection
If N = 0, returns total number of open status windows.
You can also specify a property which is a command name
and it will be called using that server connection.
/scid <-rsatM | N> [command], where N is a $cid value
/scon <-rsatM | N> [command], where N is the Nth connection
If you specify a command, the connection id is set only for
that command. The -r switch resets the connection id to the
original id for that script.
The -a and -tM switches can only be used if you specify a
-a - perform the command on all connection ids.
-tM - where M is an or'd value of 1 = server connected,
2 = not connected, 4 = connecting, 8 = not connecting.
The command is only performed if N matches the connect
status of the connection id.
Note: if you use a command that contains $identifiers, and
you want the identifiers to be evaluated in the target
connection, you must pass them as $!identifier to prevent
them from being evaulated first in the current connection.
Also added new properties to $window():
.type - returns window type name
And to $query(), $window(), $chat(), $send(), $get(), $chan(),
.cid - server connection id
.wid - window id
.hwnd - window handle
Added /server -mn switches, where -m creates a new server window
and connects, -n creates new server window without connecting.
Windows whose server connection has been closed are placed
at the end of the switchbar list. This includes things like
dcc send/get/chat, and custom windows.
Everything in mIRC now has a unique id number, all windows,
server connections, dcc sends/get/chats, etc.
The tray icon displays the animation for the current active
server connection, same goes for the Connect toolbar button,
and File menu.
Each server connection has it's own /play list, and the play
dialog shows the play list for the current active connection.
URLs list "Send To" menu, and Tray popup menu, show the network
and nickname for each status window.