Web User Interface
V10:Advanced → SIP/RTP(Tab) → SIP(Section) → SIP Header Warning
Phone User Interface
Initial Firmware Version
If this setting is "on", the warning header is displayed when the received warning code is matched with the list of accepted codes, which is specified on sip_header_warning_codes. Otherwise, it is not displayed.
deskphone: If the setting is a Snom deskphone setting