Hi, don't know if is a bug/typo or is correct, so I'm posting here. I'm noticed that in sofia_answer_channel (@mod_sofia.c:738, latest git) NUTAG_INCLUDE_EXTRA_SDP(1) is always added. Since we're into soa mode, maybe it should be added only by testing if 100rel is disabled, so it should be: --- mod_sofia.c.orig 2011-05-26 14:16:34.000000000 +0200 +++ mod_sofia.c 2011-05-26 14:16:47.000000000 +0200 @@ -734,7 +734,8 @@ SIPTAG_CONTACT_STR(tech_pvt->reply_contact), SIPTAG_CALL_INFO_STR(switch_channel_get_variable(tech_pvt->channel, SOFIA_SIP_HEADER_PREFIX "call_info")), SOATAG_USER_SDP_STR(tech_pvt->local_sdp_str), - SOATAG_REUSE_REJECTED(1), SOATAG_ORDERED_USER(1), SOATAG_AUDIO_AUX("cn telephone-event"),NUTAG_INCLUDE_EXTRA_SDP(1), + SOATAG_REUSE_REJECTED(1), SOATAG_ORDERED_USER(1), SOATAG_AUDIO_AUX("cn telephone-event"), + TAG_IF(sofia_test_pflag(tech_pvt->profile, PFLAG_DISABLE_100REL), NUTAG_INCLUDE_EXTRA_SDP(1)), TAG_IF(!zstr(extra_headers), SIPTAG_HEADER_STR(extra_headers)), TAG_IF(switch_stristr("update_display", tech_pvt->x_freeswitch_support_remote), SIPTAG_HEADER_STR("X-FS-Support: " FREESWITCH_SUPPORT)), TAG_END()); Or is correct to add it always? I've had to fix that because my upstream provider requires 100rel and does not want sdp in 200OK if is not changed from last progress message. Regards, Matteo