--- a/res/res_pjsip_outbound_registration.c
+++ b/res/res_pjsip_outbound_registration.c
@@ -209,6 +209,9 @@
                                <configOption name="support_outbound">
                                        <synopsis>Enables advertising SIP Outbound support (RFC5626) for outbound REGISTER requests.</synopsis>
                                </configOption>
+                               <configOption name="user_agent">
+                                       <synopsis>Overrides the User-Agent-Header that should be used for outbound REGISTER requests.</synopsis>
+                               </configOption>
                        </configObject>
                </configFile>
        </configInfo>
@@ -341,6 +344,8 @@ struct sip_outbound_registration {
                AST_STRING_FIELD(outbound_proxy);
                /*! \brief Endpoint to use for related incoming calls */
                AST_STRING_FIELD(endpoint);
+               /*! \brief User-Agent to use when sending the REGISTER-request */
+               AST_STRING_FIELD(user_agent);
        );
        /*! \brief Requested expiration time */
        unsigned int expiration;
@@ -431,6 +436,8 @@ struct sip_outbound_registration_client_state {
        char *registration_name;
        /*! \brief Expected time of registration lapse/expiration */
        unsigned int registration_expires;
+       /*! \brief The value for the User-Agent header sent in requests */
+       char *user_agent;
 };

 /*! \brief Outbound registration state information (persists for lifetime that registration should exist) */
@@ -726,6 +733,26 @@ static pj_status_t registration_client_send(struct sip_outbound_registration_cli
        add_security_headers(client_state, tdata);

        /*
+        * Replace the User-Agent-header if a different one should be used
+        */
+       if(!ast_strlen_zero(client_state->user_agent)) {
+               static const pj_str_t user_agent_str = { "User-Agent", 10 };
+               pjsip_generic_string_hdr *user_agent_hdr;
+               pj_str_t user_agent_val;
+               user_agent_hdr = pjsip_msg_find_hdr_by_name(tdata->msg, &user_agent_str, NULL);
+               if(user_agent_hdr) {
+                       pj_list_erase(user_agent_hdr);
+               }
+               user_agent_val = pj_str(client_state->user_agent);
+               user_agent_hdr = pjsip_generic_string_hdr_create(tdata->pool, &user_agent_str, &user_agent_val);
+               if (!user_agent_hdr) {
+                       ast_log(LOG_ERROR, "Failed to create User-Agent header\n");
+               } else {
+                       pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)user_agent_hdr);
+               }
+       }
+
+       /*
         * Set the transport in case transports were reloaded.
         * When pjproject removes the extraneous error messages produced,
         * we can check status and only set the transport and resend if there was an error
@@ -1523,6 +1550,7 @@ static struct sip_outbound_registration_state *sip_outbound_registration_state_a
        state->client_state->transport_name = ast_strdup(registration->transport);
        state->client_state->registration_name =
                ast_strdup(ast_sorcery_object_get_id(registration));
+       state->client_state->user_agent = ast_strdup(registration->user_agent);

        ast_statsd_log_string("PJSIP.registrations.count", AST_STATSD_GAUGE, "+1", 1.0);
        ast_statsd_log_string_va("PJSIP.registrations.state.%s", AST_STATSD_GAUGE, "+1", 1.0,
@@ -2759,6 +2787,7 @@ static int load_module(void)
        ast_sorcery_object_field_register_custom(ast_sip_get_sorcery(), "registration", "security_mechanisms", "", security_mechanisms_handler, NULL, NULL, 0, 0);
        ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "line", "no", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, line));
        ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "endpoint", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, endpoint));
+       ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "user_agent", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, user_agent));

        /*
         * Register sorcery observers.