I have a Mitel 5304 IP phone that I have successfully configured for SIP and am able to place and receive calls. How can I get the latest firmware for this phone? And how can I setup a 2nd SIP registration for line 2? When I access the phone by IP address the configuration options presented are very basic, there is no option for line 2. There's only one screen with username, authentication, SIP server, and provisioning server.
