diff --git a/src/mod/applications/mod_dptools/mod_dptools.c b/src/mod/applications/mod_dptools/mod_dptools.c
index e52d9b0e77..d55541a0a9 100644
--- a/src/mod/applications/mod_dptools/mod_dptools.c
+++ b/src/mod/applications/mod_dptools/mod_dptools.c
@@ -989,7 +989,7 @@ SWITCH_STANDARD_APP(event_function)
 						if (!strcasecmp(var,"Event-Name")) {
 							switch_name_event(val, &event->event_id);
 							switch_event_del_header(event, var);
-							switch_event_add_header(event, SWITCH_STACK_BOTTOM, var, "%s", val);
+							switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, var, val);
 						} else if (!strcasecmp(var,"Event-Subclass")) {
 							size_t len = strlen(val) + 1;
 							void *new = malloc(len);
@@ -997,7 +997,7 @@ SWITCH_STANDARD_APP(event_function)
 							memcpy(new, val, len);
 							event->subclass_name = new;
 						} else {
-							switch_event_add_header(event, SWITCH_STACK_BOTTOM, var, "%s", val);
+							switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, var, val);
 						}
 					}
 				}
diff --git a/src/mod/applications/mod_vmd/mod_vmd.c b/src/mod/applications/mod_vmd/mod_vmd.c
index c049dddb5a..992aac16ac 100644
--- a/src/mod/applications/mod_vmd/mod_vmd.c
+++ b/src/mod/applications/mod_vmd/mod_vmd.c
@@ -323,7 +323,7 @@ static void find_beep(vmd_session_info_t * vmd_info, switch_frame_t * frame)
 
             switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "Beep-Status", "stop");
             switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Beep-Time", "%d", (int) vmd_info->timestamp / POINTS);
-            switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Unique-ID", "%s", switch_core_session_get_uuid(vmd_info->session));
+            switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "Unique-ID", switch_core_session_get_uuid(vmd_info->session));
             switch_event_add_header(event, SWITCH_STACK_BOTTOM, "Frequency", "%6.4lf", vmd_info->beep_freq);
             switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "call-command", "vmd");
 
diff --git a/src/mod/applications/mod_voicemail/mod_voicemail.c b/src/mod/applications/mod_voicemail/mod_voicemail.c
index 6f5deec87e..a5e62fffcf 100644
--- a/src/mod/applications/mod_voicemail/mod_voicemail.c
+++ b/src/mod/applications/mod_voicemail/mod_voicemail.c
@@ -1647,7 +1647,7 @@ static void update_mwi(vm_profile_t *profile, const char *id, const char *domain
 	if (total_new_messages || total_new_urgent_messages) {
 		yn = "yes";
 	}
-	switch_event_add_header(event, SWITCH_STACK_BOTTOM, "MWI-Messages-Waiting", "%s", yn);
+	switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "MWI-Messages-Waiting", yn);
 	switch_event_add_header(event, SWITCH_STACK_BOTTOM, "MWI-Message-Account", "%s@%s", id, domain_name);
 	switch_event_add_header(event, SWITCH_STACK_BOTTOM, "MWI-Voice-Message", "%d/%d (%d/%d)", total_new_messages, total_saved_messages, total_new_urgent_messages, total_saved_urgent_messages);
 	switch_event_fire(&event);
diff --git a/src/mod/endpoints/mod_alsa/mod_alsa.c b/src/mod/endpoints/mod_alsa/mod_alsa.c
index 4fc3008bd1..e7431252e4 100644
--- a/src/mod/endpoints/mod_alsa/mod_alsa.c
+++ b/src/mod/endpoints/mod_alsa/mod_alsa.c
@@ -251,8 +251,8 @@ static switch_status_t channel_on_init(switch_core_session_t *session)
 				snprintf(buf, sizeof(buf), "BRRRRING! BRRRRING! call %s\n", tech_pvt->call_id);
 
 				if (switch_event_create_subclass(&event, SWITCH_EVENT_CUSTOM, MY_EVENT_RINGING) == SWITCH_STATUS_SUCCESS) {
-					switch_event_add_header(event, SWITCH_STACK_BOTTOM, "event_info", "%s", buf);
-					switch_event_add_header(event, SWITCH_STACK_BOTTOM, "call_id", "%s", tech_pvt->call_id);
+					switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "event_info", buf);
+					switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "call_id", tech_pvt->call_id);
 					switch_channel_event_set_data(channel, event);
 					switch_event_fire(&event);
 				}
diff --git a/src/mod/endpoints/mod_sofia/sofia.c b/src/mod/endpoints/mod_sofia/sofia.c
index 0d33b57277..0f867f69ab 100644
--- a/src/mod/endpoints/mod_sofia/sofia.c
+++ b/src/mod/endpoints/mod_sofia/sofia.c
@@ -235,14 +235,14 @@ void sofia_handle_sip_i_notify(switch_core_session_t *session, int status,
 
 	/* dispatch freeswitch event */
 	if (switch_event_create(&s_event, SWITCH_EVENT_NOTIFY_IN) == SWITCH_STATUS_SUCCESS) {
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "event", "%s", sip->sip_event->o_type);
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "pl_data", "%s", sip->sip_payload->pl_data);
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "sip_content_type", "%s", sip->sip_content_type->c_type);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "event", sip->sip_event->o_type);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "pl_data", sip->sip_payload->pl_data);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "sip_content_type", sip->sip_content_type->c_type);
 		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "port", "%d", sofia_private->gateway->profile->sip_port);
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "module_name", "%s", "mod_sofia");
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "profile_name", "%s", sofia_private->gateway->profile->name);
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "profile_uri", "%s", sofia_private->gateway->profile->url);
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "gateway_name", "%s", sofia_private->gateway->name);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "module_name", "mod_sofia");
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "profile_name", sofia_private->gateway->profile->name);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "profile_uri", sofia_private->gateway->profile->url);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "gateway_name", sofia_private->gateway->name);
 		switch_event_fire(&s_event);
 		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "dispatched freeswitch event for message-summary NOTIFY\n");
 	} else {
diff --git a/src/mod/endpoints/mod_sofia/sofia_reg.c b/src/mod/endpoints/mod_sofia/sofia_reg.c
index 2c9710afd1..17dbba4f1a 100644
--- a/src/mod/endpoints/mod_sofia/sofia_reg.c
+++ b/src/mod/endpoints/mod_sofia/sofia_reg.c
@@ -97,8 +97,8 @@ static void sofia_reg_kill_reg(sofia_gateway_t *gateway_ptr)
 static void sofia_reg_fire_custom_gateway_state_event(sofia_gateway_t *gateway) {
 	switch_event_t *s_event;
 	if (switch_event_create_subclass(&s_event, SWITCH_EVENT_CUSTOM, MY_EVENT_GATEWAY_STATE) == SWITCH_STATUS_SUCCESS) {
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "Gateway", "%s", gateway->name);
-		switch_event_add_header(s_event, SWITCH_STACK_BOTTOM, "State", "%s", sofia_state_string(gateway->state));
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "Gateway", gateway->name);
+		switch_event_add_header_string(s_event, SWITCH_STACK_BOTTOM, "State", sofia_state_string(gateway->state));
 		switch_event_fire(&s_event);
 	}
 }
diff --git a/src/mod/event_handlers/mod_event_socket/mod_event_socket.c b/src/mod/event_handlers/mod_event_socket/mod_event_socket.c
index 8f2e2484ad..4876c2f011 100644
--- a/src/mod/event_handlers/mod_event_socket/mod_event_socket.c
+++ b/src/mod/event_handlers/mod_event_socket/mod_event_socket.c
@@ -1043,7 +1043,7 @@ static switch_status_t read_packet(listener_t *listener, switch_event_t **event,
 					count++;
 					if (count == 1) {
 						switch_event_create(event, SWITCH_EVENT_COMMAND);
-						switch_event_add_header(*event, SWITCH_STACK_BOTTOM, "Command", "%s", mbuf);
+						switch_event_add_header_string(*event, SWITCH_STACK_BOTTOM, "Command", mbuf);
 					} else if (cur) {
 						char *var, *val;
 						var = cur;