diff --git a/src/amf/amf-sm.c b/src/amf/amf-sm.c
index 618621cd3..42fb92c75 100644
--- a/src/amf/amf-sm.c
+++ b/src/amf/amf-sm.c
@@ -20,6 +20,7 @@
 #include "sbi-path.h"
 #include "ngap-path.h"
 #include "nas-path.h"
+#include "ngap-handler.h"
 #include "nnrf-handler.h"
 #include "namf-handler.h"
 #include "nsmf-handler.h"
@@ -643,11 +644,29 @@ void amf_state_operational(ogs_fsm_t *s, amf_event_t *e)
     case AMF_EVT_NGAP_TIMER:
         ran_ue = e->ran_ue;
         ogs_assert(ran_ue);
-        gnb = e->gnb;
-        ogs_assert(gnb);
-        ogs_assert(OGS_FSM_STATE(&gnb->sm));
 
-        ogs_fsm_dispatch(&gnb->sm, e);
+        switch (e->timer_id) {
+        case AMF_TIMER_NG_DELAYED_SEND:
+            gnb = e->gnb;
+            ogs_assert(gnb);
+            pkbuf = e->pkbuf;
+            ogs_assert(pkbuf);
+
+            ogs_expect(OGS_OK == ngap_send_to_ran_ue(ran_ue, pkbuf));
+            ogs_timer_delete(e->timer);
+            break;
+        case AMF_TIMER_NG_HOLDING:
+            ogs_warn("Implicit NG release");
+            ogs_warn("    RAN_UE_NGAP_ID[%d] AMF_UE_NGAP_ID[%lld]",
+                  ran_ue->ran_ue_ngap_id,
+                  (long long)ran_ue->amf_ue_ngap_id);
+            ngap_handle_ue_context_release_action(ran_ue);
+            break;
+        default:
+            ogs_error("Unknown timer[%s:%d]",
+                    amf_timer_get_name(e->timer_id), e->timer_id);
+            break;
+        }
         break;
 
     case AMF_EVT_5GMM_MESSAGE:
@@ -708,12 +727,21 @@ void amf_state_operational(ogs_fsm_t *s, amf_event_t *e)
             /* If NAS(amf_ue_t) has already been associated with
              * older NG(ran_ue_t) context */
             if (CM_CONNECTED(amf_ue)) {
-               /* Implcit NG release */
-                ogs_debug("[%s] Implicit NG release", amf_ue->suci);
+                /* Previous NG(ran_ue_t) context the holding timer(30secs)
+                 * is started.
+                 * Newly associated NG(ran_ue_t) context holding timer
+                 * is stopped. */
+                ogs_debug("[%s] Start NG Holding Timer", amf_ue->suci);
                 ogs_debug("[%s]    RAN_UE_NGAP_ID[%d] AMF_UE_NGAP_ID[%lld]",
                         amf_ue->suci, amf_ue->ran_ue->ran_ue_ngap_id,
                         (long long)amf_ue->ran_ue->amf_ue_ngap_id);
-                ran_ue_remove(amf_ue->ran_ue);
+
+                /* De-associate NG with NAS/EMM */
+                ran_ue_deassociate(amf_ue->ran_ue);
+
+                ngap_send_ran_ue_context_release_command(amf_ue->ran_ue,
+                        NGAP_Cause_PR_nas, NGAP_CauseNas_normal_release,
+                        NGAP_UE_CTX_REL_NG_CONTEXT_REMOVE, 0);
             }
             amf_ue_associate_ran_ue(amf_ue, ran_ue);
         }
diff --git a/src/amf/context.c b/src/amf/context.c
index 3cda22a86..8d2ee4780 100644
--- a/src/amf/context.c
+++ b/src/amf/context.c
@@ -965,6 +965,9 @@ ran_ue_t *ran_ue_add(amf_gnb_t *gnb, uint32_t ran_ue_ngap_id)
 
     ran_ue->gnb = gnb;
 
+    ran_ue->t_ng_holding = ogs_timer_add(
+            ogs_app()->timer_mgr, amf_timer_ng_holding_timer_expire, ran_ue);
+
     ogs_list_add(&gnb->ran_ue_list, ran_ue);
 
     return ran_ue;
@@ -980,6 +983,8 @@ void ran_ue_remove(ran_ue_t *ran_ue)
 
     ogs_list_remove(&ran_ue->gnb->ran_ue_list, ran_ue);
 
+    ogs_timer_delete(ran_ue->t_ng_holding);
+
     ogs_pool_free(&ran_ue_pool, ran_ue);
 }
 
diff --git a/src/amf/context.h b/src/amf/context.h
index f3791d986..1b0bf79b7 100644
--- a/src/amf/context.h
+++ b/src/amf/context.h
@@ -173,6 +173,9 @@ struct ran_ue_s {
         ogs_nr_cgi_t    nr_cgi;
     } saved;
 
+    /* NG Holding timer for removing this context */
+    ogs_timer_t     *t_ng_holding;
+
     /* Store by UE Context Release Command
      * Retrieve by UE Context Release Complete */
 #define NGAP_UE_CTX_REL_INVALID_ACTION                      0
diff --git a/src/amf/ngap-handler.c b/src/amf/ngap-handler.c
index b1d557f04..b808bd26b 100644
--- a/src/amf/ngap-handler.c
+++ b/src/amf/ngap-handler.c
@@ -419,12 +419,21 @@ void ngap_handle_initial_ue_message(amf_gnb_t *gnb, ogs_ngap_message_t *message)
                 /* If NAS(amf_ue_t) has already been associated with
                  * older NG(ran_ue_t) context */
                 if (CM_CONNECTED(amf_ue)) {
-                   /* Implcit NG release */
-                    ogs_debug("Implicit NG release");
-                    ogs_debug("    RAN_UE_NGAP_ID[%d] AMF_UE_NGAP_ID[%lld]",
-                          amf_ue->ran_ue->ran_ue_ngap_id,
-                          (long long)amf_ue->ran_ue->amf_ue_ngap_id);
-                    ran_ue_remove(amf_ue->ran_ue);
+                    /* Previous NG(ran_ue_t) context the holding timer(30secs)
+                     * is started.
+                     * Newly associated NG(ran_ue_t) context holding timer
+                     * is stopped. */
+                    ogs_debug("[%s] Start NG Holding Timer", amf_ue->suci);
+                    ogs_debug("[%s]    RAN_UE_NGAP_ID[%d] AMF_UE_NGAP_ID[%lld]",
+                            amf_ue->suci, amf_ue->ran_ue->ran_ue_ngap_id,
+                            (long long)amf_ue->ran_ue->amf_ue_ngap_id);
+
+                    /* De-associate NG with NAS/EMM */
+                    ran_ue_deassociate(amf_ue->ran_ue);
+
+                    ngap_send_ran_ue_context_release_command(amf_ue->ran_ue,
+                            NGAP_Cause_PR_nas, NGAP_CauseNas_normal_release,
+                            NGAP_UE_CTX_REL_NG_CONTEXT_REMOVE, 0);
                 }
                 amf_ue_associate_ran_ue(amf_ue, ran_ue);
             }
@@ -1185,7 +1194,7 @@ void ngap_handle_ue_context_release_request(
         if (amf_sess_xact_count(amf_ue) == xact_count)
             ngap_send_amf_ue_context_release_command(amf_ue,
                     NGAP_Cause_PR_nas, NGAP_CauseNas_normal_release,
-                    NGAP_UE_CTX_REL_NG_CONTEXT_REMOVE, 0);
+                    NGAP_UE_CTX_REL_NG_REMOVE_AND_UNLINK, 0);
     }
 }
 
@@ -1196,7 +1205,6 @@ void ngap_handle_ue_context_release_complete(
     char buf[OGS_ADDRSTRLEN];
     uint64_t amf_ue_ngap_id;
 
-    amf_ue_t *amf_ue = NULL;
     ran_ue_t *ran_ue = NULL;
 
     NGAP_SuccessfulOutcome_t *successfulOutcome = NULL;
@@ -1260,11 +1268,20 @@ void ngap_handle_ue_context_release_complete(
         return;
     }
 
-    ogs_debug("    RAN_UE_NGAP_ID[%d] AMF_UE_NGAP_ID[%lld]",
-            ran_ue->ran_ue_ngap_id, (long long)ran_ue->amf_ue_ngap_id);
+    ngap_handle_ue_context_release_action(ran_ue);
+}
+
+void ngap_handle_ue_context_release_action(ran_ue_t *ran_ue)
+{
+    amf_ue_t *amf_ue = NULL;
+
+    ogs_assert(ran_ue);
 
     amf_ue = ran_ue->amf_ue;
 
+    ogs_debug("    RAN_UE_NGAP_ID[%d] AMF_UE_NGAP_ID[%lld]",
+            ran_ue->ran_ue_ngap_id, (long long)ran_ue->amf_ue_ngap_id);
+
     switch (ran_ue->ue_ctx_rel_action) {
     case NGAP_UE_CTX_REL_NG_CONTEXT_REMOVE:
         ogs_debug("    Action: NG context remove");
diff --git a/src/amf/ngap-handler.h b/src/amf/ngap-handler.h
index ab7f85f1b..36bdca1df 100644
--- a/src/amf/ngap-handler.h
+++ b/src/amf/ngap-handler.h
@@ -53,6 +53,7 @@ void ngap_handle_ue_context_release_request(
         amf_gnb_t *gnb, ogs_ngap_message_t *message);
 void ngap_handle_ue_context_release_complete(
         amf_gnb_t *gnb, ogs_ngap_message_t *message);
+void ngap_handle_ue_context_release_action(ran_ue_t *ran_ue);
 
 void ngap_handle_path_switch_request(
         amf_gnb_t *gnb, ogs_ngap_message_t *message);
diff --git a/src/amf/nsmf-handler.c b/src/amf/nsmf-handler.c
index 900a702e4..a8c5148f1 100644
--- a/src/amf/nsmf-handler.c
+++ b/src/amf/nsmf-handler.c
@@ -288,7 +288,7 @@ int amf_nsmf_pdu_session_handle_update_sm_context(
                 if (SESSION_SYNC_DONE(amf_ue)) {
                     ngap_send_amf_ue_context_release_command(amf_ue,
                             NGAP_Cause_PR_nas, NGAP_CauseNas_normal_release,
-                            NGAP_UE_CTX_REL_NG_CONTEXT_REMOVE, 0);
+                            NGAP_UE_CTX_REL_NG_REMOVE_AND_UNLINK, 0);
                 }
 
             } else if (state == AMF_UPDATE_SM_CONTEXT_ACTIVATING) {
diff --git a/src/amf/timer.c b/src/amf/timer.c
index 9a4a0232e..07b5e72e4 100644
--- a/src/amf/timer.c
+++ b/src/amf/timer.c
@@ -50,6 +50,9 @@ static amf_timer_cfg_t g_amf_timer_cfg[MAX_NUM_OF_AMF_TIMER] = {
     /* IDENTITY REQUEST sent */
     [AMF_TIMER_T3570] =
         { .max_count = 4, .duration = ogs_time_from_sec(3) },
+
+    [AMF_TIMER_NG_HOLDING] =
+        { .duration = ogs_time_from_sec(3) },
 };
 
 static void gmm_timer_event_send(
@@ -90,6 +93,8 @@ const char *amf_timer_get_name(amf_timer_e id)
         return "AMF_TIMER_T3560";
     case AMF_TIMER_T3570:
         return "AMF_TIMER_T3570";
+    case AMF_TIMER_NG_HOLDING:
+        return "AMF_TIMER_NG_HOLDING";
     default: 
        break;
     }
@@ -222,3 +227,24 @@ void amf_timer_t3570_expire(void *data)
 {
     gmm_timer_event_send(AMF_TIMER_T3570, data);
 }
+
+void amf_timer_ng_holding_timer_expire(void *data)
+{
+    int rv;
+    amf_event_t *e = NULL;
+    ran_ue_t *ran_ue = NULL;
+
+    ogs_assert(data);
+    ran_ue = data;
+
+    e = amf_event_new(AMF_EVT_NGAP_TIMER);
+
+    e->timer_id = AMF_TIMER_NG_HOLDING;
+    e->ran_ue = ran_ue;
+
+    rv = ogs_queue_push(ogs_app()->queue, e);
+    if (rv != OGS_OK) {
+        ogs_warn("ogs_queue_push() failed:%d", (int)rv);
+        amf_event_free(e);
+    }
+}
diff --git a/src/amf/timer.h b/src/amf/timer.h
index ccce6cd7f..db751b8ca 100644
--- a/src/amf/timer.h
+++ b/src/amf/timer.h
@@ -38,6 +38,7 @@ typedef enum {
     AMF_TIMER_SBI_CLIENT_WAIT,
 
     AMF_TIMER_NG_DELAYED_SEND,
+    AMF_TIMER_NG_HOLDING,
 
     AMF_TIMER_T3513,
     AMF_TIMER_T3522,
@@ -75,6 +76,8 @@ void amf_timer_t3555_expire(void *data);
 void amf_timer_t3560_expire(void *data);
 void amf_timer_t3570_expire(void *data);
 
+void amf_timer_ng_holding_timer_expire(void *data);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/mme/mme-path.c b/src/mme/mme-path.c
index cc4e9c2d8..dac103f3a 100644
--- a/src/mme/mme-path.c
+++ b/src/mme/mme-path.c
@@ -84,6 +84,6 @@ void mme_send_release_access_bearer_or_ue_context_release(enb_ue_t *enb_ue)
         ogs_debug("No UE Context");
         s1ap_send_ue_context_release_command(enb_ue, 
                 S1AP_Cause_PR_nas, S1AP_CauseNas_normal_release,
-                S1AP_UE_CTX_REL_S1_CONTEXT_REMOVE, 0);
+                S1AP_UE_CTX_REL_S1_REMOVE_AND_UNLINK, 0);
     }
 }
diff --git a/src/mme/mme-sm.c b/src/mme/mme-sm.c
index 9629b91f9..d67f50e58 100644
--- a/src/mme/mme-sm.c
+++ b/src/mme/mme-sm.c
@@ -327,8 +327,8 @@ void mme_state_operational(ogs_fsm_t *s, mme_event_t *e)
                  * is started.
                  * Newly associated S1(enb_ue_t) context holding timer
                  * is stopped. */
-                ogs_debug("Start S1 Holding Timer\n");
-                ogs_debug("    ENB_UE_S1AP_ID[%d] MME_UE_S1AP_ID[%d]\n",
+                ogs_debug("Start S1 Holding Timer");
+                ogs_debug("    ENB_UE_S1AP_ID[%d] MME_UE_S1AP_ID[%d]",
                         mme_ue->enb_ue->enb_ue_s1ap_id,
                         mme_ue->enb_ue->mme_ue_s1ap_id);
 
diff --git a/src/mme/s1ap-handler.c b/src/mme/s1ap-handler.c
index b655c8c4c..babd52454 100644
--- a/src/mme/s1ap-handler.c
+++ b/src/mme/s1ap-handler.c
@@ -292,8 +292,8 @@ void s1ap_handle_initial_ue_message(mme_enb_t *enb, ogs_s1ap_message_t *message)
                      * is started.
                      * Newly associated S1(enb_ue_t) context holding timer
                      * is stopped. */
-                    ogs_debug("Start S1 Holding Timer\n");
-                    ogs_debug("    ENB_UE_S1AP_ID[%d] MME_UE_S1AP_ID[%d]\n",
+                    ogs_debug("Start S1 Holding Timer");
+                    ogs_debug("    ENB_UE_S1AP_ID[%d] MME_UE_S1AP_ID[%d]",
                             mme_ue->enb_ue->enb_ue_s1ap_id,
                             mme_ue->enb_ue->mme_ue_s1ap_id);
 
diff --git a/tests/common/ngap-handler.c b/tests/common/ngap-handler.c
index 6097ddfd1..4537a650d 100644
--- a/tests/common/ngap-handler.c
+++ b/tests/common/ngap-handler.c
@@ -76,6 +76,7 @@ void testngap_handle_downlink_nas_transport(
 
     NGAP_DownlinkNASTransport_IEs_t *ie = NULL;
     NGAP_AMF_UE_NGAP_ID_t *AMF_UE_NGAP_ID = NULL;
+    NGAP_RAN_UE_NGAP_ID_t *RAN_UE_NGAP_ID = NULL;
     NGAP_NAS_PDU_t *NAS_PDU = NULL;
 
     ogs_assert(test_ue);
@@ -93,6 +94,9 @@ void testngap_handle_downlink_nas_transport(
         case NGAP_ProtocolIE_ID_id_AMF_UE_NGAP_ID:
             AMF_UE_NGAP_ID = &ie->value.choice.AMF_UE_NGAP_ID;
             break;
+        case NGAP_ProtocolIE_ID_id_RAN_UE_NGAP_ID:
+            RAN_UE_NGAP_ID = &ie->value.choice.RAN_UE_NGAP_ID;
+            break;
         case NGAP_ProtocolIE_ID_id_NAS_PDU:
             NAS_PDU = &ie->value.choice.NAS_PDU;
             break;
@@ -101,8 +105,14 @@ void testngap_handle_downlink_nas_transport(
         }
     }
 
-    ogs_assert(AMF_UE_NGAP_ID);
-    asn_INTEGER2ulong(AMF_UE_NGAP_ID, &test_ue->amf_ue_ngap_id);
+    if (AMF_UE_NGAP_ID) {
+        uint64_t amf_ue_ngap_id;
+        asn_INTEGER2ulong(AMF_UE_NGAP_ID, (unsigned long *)&amf_ue_ngap_id);
+        test_ue->amf_ue_ngap_id = (uint64_t)amf_ue_ngap_id;
+    }
+    if (RAN_UE_NGAP_ID) {
+        test_ue->ran_ue_ngap_id = *RAN_UE_NGAP_ID;
+    }
 
     if (NAS_PDU)
         testngap_send_to_nas(test_ue, NAS_PDU);
@@ -120,6 +130,7 @@ void testngap_handle_initial_context_setup_request(
 
     NGAP_InitialContextSetupRequestIEs_t *ie = NULL;
     NGAP_AMF_UE_NGAP_ID_t *AMF_UE_NGAP_ID = NULL;
+    NGAP_RAN_UE_NGAP_ID_t *RAN_UE_NGAP_ID = NULL;
     NGAP_NAS_PDU_t *NAS_PDU = NULL;
 
     ogs_assert(test_ue);
@@ -137,6 +148,9 @@ void testngap_handle_initial_context_setup_request(
         case NGAP_ProtocolIE_ID_id_AMF_UE_NGAP_ID:
             AMF_UE_NGAP_ID = &ie->value.choice.AMF_UE_NGAP_ID;
             break;
+        case NGAP_ProtocolIE_ID_id_RAN_UE_NGAP_ID:
+            RAN_UE_NGAP_ID = &ie->value.choice.RAN_UE_NGAP_ID;
+            break;
         case NGAP_ProtocolIE_ID_id_NAS_PDU:
             NAS_PDU = &ie->value.choice.NAS_PDU;
             break;
@@ -150,6 +164,9 @@ void testngap_handle_initial_context_setup_request(
         asn_INTEGER2ulong(AMF_UE_NGAP_ID, (unsigned long *)&amf_ue_ngap_id);
         test_ue->amf_ue_ngap_id = (uint64_t)amf_ue_ngap_id;
     }
+    if (RAN_UE_NGAP_ID) {
+        test_ue->ran_ue_ngap_id = *RAN_UE_NGAP_ID;
+    }
 
     if (NAS_PDU)
         testngap_send_to_nas(test_ue, NAS_PDU);
@@ -191,10 +208,14 @@ void testngap_handle_ue_release_context_command(
     if (UE_NGAP_IDs) {
         if (UE_NGAP_IDs->present == NGAP_UE_NGAP_IDs_PR_uE_NGAP_ID_pair) {
             uint64_t amf_ue_ngap_id;
+            uint64_t ran_ue_ngap_id;
             asn_INTEGER2ulong(
                 &UE_NGAP_IDs->choice.uE_NGAP_ID_pair->aMF_UE_NGAP_ID,
                 (unsigned long *)&amf_ue_ngap_id);
             test_ue->amf_ue_ngap_id = (uint64_t)amf_ue_ngap_id;
+
+            test_ue->ran_ue_ngap_id =
+                UE_NGAP_IDs->choice.uE_NGAP_ID_pair->rAN_UE_NGAP_ID;
         }
     }
 }
diff --git a/tests/registration/dereg-test.c b/tests/registration/dereg-test.c
index f25e8f190..97aad9475 100644
--- a/tests/registration/dereg-test.c
+++ b/tests/registration/dereg-test.c
@@ -318,6 +318,8 @@ static void test1_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -579,6 +581,8 @@ static void test2_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -1010,6 +1014,27 @@ static void test3_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     ogs_pkbuf_free(recvbuf);
 
+    /* Send De-registration request */
+    gmmbuf = testgmm_build_de_registration_request(test_ue, 1);
+    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);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -1351,6 +1376,8 @@ static void test4_func(abts_case *tc, void *data)
         ABTS_INT_EQUAL(tc, OGS_OK, rv);
     }
 
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
diff --git a/tests/registration/guti-test.c b/tests/registration/guti-test.c
index aae7400fa..f2a15b212 100644
--- a/tests/registration/guti-test.c
+++ b/tests/registration/guti-test.c
@@ -332,6 +332,17 @@ static void test1_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    /* OLD Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send OLD UE Context Release Complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Receive Registration accept */
     recvbuf = testgnb_ngap_read(ngap);
     ABTS_PTR_NOTNULL(tc, recvbuf);
@@ -478,6 +489,27 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     ogs_pkbuf_free(recvbuf);
 
+    /* Send UE context release request */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
diff --git a/tests/registration/identity-test.c b/tests/registration/identity-test.c
index 7f5618235..f2eff7bb7 100644
--- a/tests/registration/identity-test.c
+++ b/tests/registration/identity-test.c
@@ -281,6 +281,17 @@ static void test1_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    /* OLD Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send OLD UE Context Release Complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Receive Initial context setup request */
     recvbuf = testgnb_ngap_read(ngap);
     ABTS_PTR_NOTNULL(tc, recvbuf);
diff --git a/tests/registration/idle-test.c b/tests/registration/idle-test.c
index ae1e55ec7..dea957d6c 100644
--- a/tests/registration/idle-test.c
+++ b/tests/registration/idle-test.c
@@ -430,6 +430,27 @@ static void test1_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     ogs_pkbuf_free(recvbuf);
 
+    /* Send UE context release request */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -718,6 +739,27 @@ static void test2_func(abts_case *tc, void *data)
     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,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -1029,6 +1071,17 @@ static void test3_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    /* OLD Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send OLD UE Context Release Complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Receive Service accept */
     recvbuf = testgnb_ngap_read(ngap);
     ABTS_PTR_NOTNULL(tc, recvbuf);
@@ -1084,6 +1137,27 @@ static void test3_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     ogs_pkbuf_free(recvbuf);
 
+    /* Send UE context release request */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -1454,6 +1528,17 @@ static void test4_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    /* OLD Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send OLD UE Context Release Complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
     /* Receive Service accept */
     recvbuf = testgnb_ngap_read(ngap);
     ABTS_PTR_NOTNULL(tc, recvbuf);
@@ -1567,6 +1652,8 @@ static void test4_func(abts_case *tc, void *data)
     rv = testgnb_ngap_send(ngap, sendbuf);
     ABTS_INT_EQUAL(tc, OGS_OK, rv);
 
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -1947,6 +2034,27 @@ static void test5_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     ogs_pkbuf_free(recvbuf);
 
+    /* Send UE context release request */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);
@@ -2338,6 +2446,27 @@ static void test6_func(abts_case *tc, void *data)
     ABTS_PTR_NOTNULL(tc, recvbuf);
     ogs_pkbuf_free(recvbuf);
 
+    /* Send UE context release request */
+    sendbuf = testngap_build_ue_context_release_request(test_ue,
+            NGAP_Cause_PR_radioNetwork, NGAP_CauseRadioNetwork_user_inactivity,
+            true);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    /* Receive UE context release command */
+    recvbuf = testgnb_ngap_read(ngap);
+    ABTS_PTR_NOTNULL(tc, recvbuf);
+    testngap_recv(test_ue, recvbuf);
+
+    /* Send UE context release complete */
+    sendbuf = testngap_build_ue_context_release_complete(test_ue);
+    ABTS_PTR_NOTNULL(tc, sendbuf);
+    rv = testgnb_ngap_send(ngap, sendbuf);
+    ABTS_INT_EQUAL(tc, OGS_OK, rv);
+
+    ogs_msleep(300);
+
     /********** Remove Subscriber in Database */
     doc = BCON_NEW("imsi", BCON_UTF8(test_ue->imsi));
     ABTS_PTR_NOTNULL(tc, doc);