Abacus only supports SIPS over TLS. With SIPS over TLS, "sips" is used in all relevant headers. Abacus does not support SIP over TLS. (In SIP over TLS, "sip" is used in the header and the device will try to use TLS connection if possible. If TLS connection is not available, it will fall back to use the default -UDP connection.) That means whenever TLS is used, Abacus will always send "sips" in the header.