diff --git a/src/amf/gmm-build.c b/src/amf/gmm-build.c
index 20de7983f..cb54e34bd 100644
--- a/src/amf/gmm-build.c
+++ b/src/amf/gmm-build.c
@@ -440,8 +440,7 @@ ogs_pkbuf_t *gmm_build_security_mode_command(amf_ue_t *amf_ue)
     return nas_5gs_security_encode(amf_ue, &message);
 }
 
-ogs_pkbuf_t *gmm_build_configuration_update_command(
-        amf_ue_t *amf_ue, int ack, int red)
+ogs_pkbuf_t *gmm_build_configuration_update_command(amf_ue_t *amf_ue, int red)
 {
     ogs_nas_5gs_message_t message;
     ogs_nas_5gs_configuration_update_command_t *configuration_update_command =
@@ -451,6 +450,9 @@ ogs_pkbuf_t *gmm_build_configuration_update_command(
         &configuration_update_command->universal_time_and_local_time_zone;
     ogs_nas_daylight_saving_time_t *network_daylight_saving_time =
         &configuration_update_command->network_daylight_saving_time;
+    ogs_nas_configuration_update_indication_t
+        *configuration_update_indication =
+            &configuration_update_command->configuration_update_indication;
 
     struct timeval tv;
     struct tm gmt, local;
@@ -480,17 +482,11 @@ ogs_pkbuf_t *gmm_build_configuration_update_command(
         OGS_NAS_EXTENDED_PROTOCOL_DISCRIMINATOR_5GMM;
     message.gmm.h.message_type = OGS_NAS_5GS_CONFIGURATION_UPDATE_COMMAND;
 
-    if (ack | red) {
-        ogs_nas_configuration_update_indication_t
-            *configuration_update_indication =
-                &configuration_update_command->configuration_update_indication;
+    configuration_update_command->presencemask |=
+        OGS_NAS_5GS_CONFIGURATION_UPDATE_COMMAND_CONFIGURATION_UPDATE_INDICATION_PRESENT;
 
-        configuration_update_command->presencemask |=
-            OGS_NAS_5GS_CONFIGURATION_UPDATE_COMMAND_CONFIGURATION_UPDATE_INDICATION_PRESENT;
-
-        configuration_update_indication->ack = ack;
-        configuration_update_indication->red = red;
-    }
+    configuration_update_indication->ack = 1;
+    configuration_update_indication->red = red;
 
     configuration_update_command->presencemask |=
         OGS_NAS_5GS_CONFIGURATION_UPDATE_COMMAND_UNIVERSAL_TIME_AND_LOCAL_TIME_ZONE_PRESENT;
diff --git a/src/amf/gmm-build.h b/src/amf/gmm-build.h
index e9005c9ba..3cdc85348 100644
--- a/src/amf/gmm-build.h
+++ b/src/amf/gmm-build.h
@@ -41,8 +41,7 @@ ogs_pkbuf_t *gmm_build_security_mode_command(amf_ue_t *amf_ue);
 ogs_pkbuf_t *gmm_build_authentication_request(amf_ue_t *amf_ue);
 ogs_pkbuf_t *gmm_build_authentication_reject(void);
 
-ogs_pkbuf_t *gmm_build_configuration_update_command(
-        amf_ue_t *amf_ue, int ack, int red);
+ogs_pkbuf_t *gmm_build_configuration_update_command(amf_ue_t *amf_ue, int red);
 
 ogs_pkbuf_t *gmm_build_dl_nas_transport(amf_sess_t *sess,
         uint8_t payload_container_type, ogs_pkbuf_t *payload,
diff --git a/src/amf/gmm-sm.c b/src/amf/gmm-sm.c
index a358ad0ec..11dcd2e98 100644
--- a/src/amf/gmm-sm.c
+++ b/src/amf/gmm-sm.c
@@ -345,7 +345,7 @@ static void common_register_state(ogs_fsm_t *s, amf_event_t *e)
                  * If t3555 is timeout, the saved pkbuf is used.
                  * In this case, ack should be set to 1 for timer expiration
                  */
-                nas_5gs_send_configuration_update_command(amf_ue, 1, 0);
+                nas_5gs_send_configuration_update_command(amf_ue, 0);
             }
             break;
 
@@ -873,9 +873,18 @@ void gmm_state_initial_context_setup(ogs_fsm_t *s, amf_event_t *e)
         case OGS_NAS_5GS_REGISTRATION_COMPLETE:
             ogs_debug("[%s] Registration complete", amf_ue->supi);
 
-            /* Ack/Red to 0
-             *  - No need to receive configuration update complete */
-            nas_5gs_send_configuration_update_command(amf_ue, 0, 0);
+            /*
+             * TS24.501
+             * 5.4.4.2 Generic UE configuration update procedure initiated
+             *         by the network
+             *
+             * If an acknowledgement from the UE is requested, the AMF shall
+             * indicate acknowledgement requested in the Configuration update
+             * indication IE in the CONFIGURATION UPDATE COMMAND message and
+             * shall start timer T3555. Acknowledgement shall be requested
+             * for all parameters except when only NITZ is included.
+             */
+            nas_5gs_send_configuration_update_command(amf_ue, 0);
 
             OGS_FSM_TRAN(s, &gmm_state_registered);
             break;
diff --git a/src/amf/nas-path.c b/src/amf/nas-path.c
index 0535e1f35..21ca37778 100644
--- a/src/amf/nas-path.c
+++ b/src/amf/nas-path.c
@@ -272,8 +272,7 @@ void nas_5gs_send_security_mode_command(amf_ue_t *amf_ue)
     ogs_expect(rv == OGS_OK);
 }
 
-void nas_5gs_send_configuration_update_command(
-        amf_ue_t *amf_ue, int ack, int red)
+void nas_5gs_send_configuration_update_command(amf_ue_t *amf_ue, int red)
 {
     int rv;
     ogs_pkbuf_t *gmmbuf = NULL;
@@ -286,15 +285,13 @@ void nas_5gs_send_configuration_update_command(
         gmmbuf = amf_ue->t3555.pkbuf;
         ogs_expect_or_return(gmmbuf);
     } else {
-        gmmbuf = gmm_build_configuration_update_command(amf_ue, ack, red);
+        gmmbuf = gmm_build_configuration_update_command(amf_ue, red);
         ogs_expect_or_return(gmmbuf);
     }
 
-    if (ack) {
-        amf_ue->t3555.pkbuf = ogs_pkbuf_copy(gmmbuf);
-        ogs_timer_start(amf_ue->t3555.timer,
-                amf_timer_cfg(AMF_TIMER_T3555)->duration);
-    }
+    amf_ue->t3555.pkbuf = ogs_pkbuf_copy(gmmbuf);
+    ogs_timer_start(amf_ue->t3555.timer,
+            amf_timer_cfg(AMF_TIMER_T3555)->duration);
 
     rv = nas_5gs_send_to_downlink_nas_transport(amf_ue, gmmbuf);
     ogs_expect(rv == OGS_OK);
diff --git a/src/amf/nas-path.h b/src/amf/nas-path.h
index 72ffca790..87f0f2aaf 100644
--- a/src/amf/nas-path.h
+++ b/src/amf/nas-path.h
@@ -51,8 +51,7 @@ void nas_5gs_send_authentication_reject(amf_ue_t *amf_ue);
 
 void nas_5gs_send_security_mode_command(amf_ue_t *amf_ue);
 
-void nas_5gs_send_configuration_update_command(
-        amf_ue_t *amf_ue, int ack, int red);
+void nas_5gs_send_configuration_update_command(amf_ue_t *amf_ue, int red);
 
 void nas_send_pdu_session_establishment_accept(amf_sess_t *sess,
         ogs_pkbuf_t *n1smbuf, ogs_pkbuf_t *n2smbuf);
diff --git a/tests/registration/dereg-test.c b/tests/registration/dereg-test.c
index c5c50f0f5..1e4b9cda1 100644
--- a/tests/registration/dereg-test.c
+++ b/tests/registration/dereg-test.c
@@ -281,6 +281,14 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
@@ -292,16 +300,6 @@ static void test1_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
-#if 0 /* No need to send configuration update complete */
-    /* Send Configuration update complete */
-    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
-    ABTS_PTR_NOTNULL(tc, gmmbuf);
-    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
-    ABTS_PTR_NOTNULL(tc, sendbuf);
-    rv = testgnb_ngap_send(ngap, sendbuf);
-    ABTS_INT_EQUAL(tc, OGS_OK, rv);
-#endif
-
     /* Receive PDU session establishment accept */
     recvbuf = testgnb_ngap_read(ngap);
     ABTS_PTR_NOTNULL(tc, recvbuf);
diff --git a/tests/registration/gmm-status-test.c b/tests/registration/gmm-status-test.c
index 0d0696b37..b7da8ddd9 100644
--- a/tests/registration/gmm-status-test.c
+++ b/tests/registration/gmm-status-test.c
@@ -269,6 +269,14 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
diff --git a/tests/registration/guti-test.c b/tests/registration/guti-test.c
index 01f746794..680e27c40 100644
--- a/tests/registration/guti-test.c
+++ b/tests/registration/guti-test.c
@@ -289,6 +289,14 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
@@ -467,6 +475,14 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
@@ -793,6 +809,14 @@ static void test2_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
diff --git a/tests/registration/identity-test.c b/tests/registration/identity-test.c
index 6710f53c0..0a1c4f4af 100644
--- a/tests/registration/identity-test.c
+++ b/tests/registration/identity-test.c
@@ -275,6 +275,14 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
diff --git a/tests/registration/idle-test.c b/tests/registration/idle-test.c
index 32d8f622e..59eeaa08e 100644
--- a/tests/registration/idle-test.c
+++ b/tests/registration/idle-test.c
@@ -275,6 +275,14 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
@@ -760,6 +768,14 @@ static void test2_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send UE context release request */
     sendbuf = testngap_build_ue_context_release_request(&test_ue,
             NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
@@ -1091,6 +1107,14 @@ static void test3_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send PDU session establishment request */
     gsmbuf = testgsm_build_pdu_session_establishment_request(&test_sess);
     ABTS_PTR_NOTNULL(tc, gsmbuf);
@@ -1521,6 +1545,14 @@ static void test4_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     testngap_recv(&test_ue, recvbuf);
 
+    /* Send Configuration update complete */
+    gmmbuf = testgmm_build_configuration_update_complete(&test_ue);
+    ABTS_PTR_NOTNULL(tc, gmmbuf);
+    sendbuf = testngap_build_uplink_nas_transport(&test_ue, gmmbuf);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Send UE context release request */
     sendbuf = testngap_build_ue_context_release_request(&test_ue,
             NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,