diff --git a/src/core/ddsc/src/dds_entity.c b/src/core/ddsc/src/dds_entity.c
index 724948a..4e6a225 100644
--- a/src/core/ddsc/src/dds_entity.c
+++ b/src/core/ddsc/src/dds_entity.c
@@ -24,6 +24,7 @@
 #include "dds/version.h"
 #include "dds/ddsi/ddsi_pmd.h"
 #include "dds/ddsi/q_xqos.h"
+#include "dds/ddsi/q_transmit.h"
 
 extern inline dds_entity *dds_entity_from_handle_link (struct dds_handle_link *hdllink);
 extern inline bool dds_entity_is_enabled (const dds_entity *e);
@@ -1387,9 +1388,9 @@ dds_return_t dds_generic_unimplemented_operation (dds_entity_t handle, dds_entit
 dds_return_t dds_assert_liveliness (dds_entity_t entity)
 {
   dds_return_t rc;
-  dds_entity *e;
+  dds_entity *e, *ewr;
 
-  if ((rc = dds_entity_lock (entity, DDS_KIND_DONTCARE, &e)) != DDS_RETCODE_OK)
+  if ((rc = dds_entity_pin (entity, &e)) != DDS_RETCODE_OK)
     return rc;
   switch (dds_entity_kind (e))
   {
@@ -1398,8 +1399,11 @@ dds_return_t dds_assert_liveliness (dds_entity_t entity)
       break;
     }
     case DDS_KIND_WRITER: {
-      /* FIXME: implement liveliness manual-by-topic */
-      rc = DDS_RETCODE_UNSUPPORTED;
+      if ((rc = dds_entity_lock (entity, DDS_KIND_WRITER, &ewr)) != DDS_RETCODE_OK)
+        return rc;
+      if ((rc = write_hb_liveliness (&e->m_domain->gv, &e->m_guid, ((struct dds_writer *)ewr)->m_xp)) != DDS_RETCODE_OK)
+        return rc;
+      dds_entity_unlock (e);
       break;
     }
     default: {
@@ -1407,6 +1411,6 @@ dds_return_t dds_assert_liveliness (dds_entity_t entity)
       break;
     }
   }
-  dds_entity_unlock (e);
+  dds_entity_unpin (e);
   return rc;
 }
diff --git a/src/core/ddsc/tests/liveliness.c b/src/core/ddsc/tests/liveliness.c
index a706568..7063410 100644
--- a/src/core/ddsc/tests/liveliness.c
+++ b/src/core/ddsc/tests/liveliness.c
@@ -30,8 +30,8 @@
 
 #define DDS_DOMAINID_PUB 0
 #define DDS_DOMAINID_SUB 1
-#define DDS_CONFIG_NO_PORT_GAIN "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<General><NetworkInterfaceAddress>127.0.0.1</NetworkInterfaceAddress></General><Discovery><Ports><DomainGain>0</DomainGain></Ports></Discovery>"
-#define DDS_CONFIG_NO_PORT_GAIN_LOG "<"DDS_PROJECT_NAME"><Domain><Discovery><Ports><DomainGain>0</DomainGain></Ports></Discovery><Tracing><OutputFile>cyclonedds_liveliness.log</OutputFile><Verbosity>finest</Verbosity></Tracing></Domain></"DDS_PROJECT_NAME">"
+#define DDS_CONFIG_NO_PORT_GAIN "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Discovery><Ports><DomainGain>0</DomainGain></Ports></Discovery>"
+#define DDS_CONFIG_NO_PORT_GAIN_LOG "${CYCLONEDDS_URI}${CYCLONEDDS_URI:+,}<Tracing><OutputFile>cyclonedds_liveliness_tests.${CYCLONEDDS_DOMAIN_ID}.${CYCLONEDDS_PID}.log</OutputFile><Verbosity>finest</Verbosity></Tracing><Discovery><Ports><DomainGain>0</DomainGain></Ports></Discovery>"
 
 uint32_t g_topic_nr = 0;
 static dds_entity_t g_pub_domain = 0;
@@ -44,7 +44,7 @@ static dds_entity_t g_sub_subscriber = 0;
 
 static char *create_topic_name(const char *prefix, uint32_t nr, char *name, size_t size)
 {
-	/* Get semi random g_topic name. */
+	/* Get unique g_topic name. */
 	ddsrt_pid_t pid = ddsrt_getpid();
 	ddsrt_tid_t tid = ddsrt_gettid();
 	(void)snprintf(name, size, "%s%d_pid%" PRIdPID "_tid%" PRIdTID "", prefix, nr, pid, tid);
@@ -53,10 +53,15 @@ static char *create_topic_name(const char *prefix, uint32_t nr, char *name, size
 
 static void liveliness_init(void)
 {
-	char *conf = ddsrt_expand_envvars(DDS_CONFIG_NO_PORT_GAIN, UINT32_MAX);
-	g_pub_domain = dds_create_domain(DDS_DOMAINID_PUB, conf);
-	g_sub_domain = dds_create_domain(DDS_DOMAINID_SUB, conf);
-	dds_free(conf);
+	/* Domains for pub and sub use a different domain id, but the portgain setting
+	 * in configuration is 0, so that both domains will map to the same port number.
+	 * This allows to create two domains in a single test process. */
+	char *conf_pub = ddsrt_expand_envvars(DDS_CONFIG_NO_PORT_GAIN, DDS_DOMAINID_PUB);
+	char *conf_sub = ddsrt_expand_envvars(DDS_CONFIG_NO_PORT_GAIN, DDS_DOMAINID_SUB);
+	g_pub_domain = dds_create_domain(DDS_DOMAINID_PUB, conf_pub);
+	g_sub_domain = dds_create_domain(DDS_DOMAINID_SUB, conf_sub);
+	dds_free(conf_pub);
+	dds_free(conf_sub);
 
 	g_pub_participant = dds_create_participant(DDS_DOMAINID_PUB, NULL, NULL);
 	CU_ASSERT_FATAL(g_pub_participant > 0);
@@ -79,6 +84,11 @@ static void liveliness_fini(void)
 	dds_delete(g_pub_domain);
 }
 
+/**
+ * Gets the current PMD sequence number for the participant. This
+ * can be used to count the number of PMD messages that is sent by
+ * the participant.
+ */
 static seqno_t get_pmd_seqno(dds_entity_t participant)
 {
 	seqno_t seqno;
@@ -96,6 +106,9 @@ static seqno_t get_pmd_seqno(dds_entity_t participant)
 	return seqno;
 }
 
+/**
+ * Gets the current PMD interval for the participant
+ */
 static dds_duration_t get_pmd_interval(dds_entity_t participant)
 {
 	dds_duration_t intv;
@@ -110,6 +123,9 @@ static dds_duration_t get_pmd_interval(dds_entity_t participant)
 	return intv;
 }
 
+/**
+ * Gets the current lease duration for the participant
+ */
 static dds_duration_t get_ldur_config(dds_entity_t participant)
 {
 	struct dds_entity *pp_entity;
@@ -120,15 +136,22 @@ static dds_duration_t get_ldur_config(dds_entity_t participant)
 	return ldur;
 }
 
+
+/**
+ * Test that the correct number of PMD messages is sent for
+ * the various liveliness kinds.
+ */
 #define A DDS_LIVELINESS_AUTOMATIC
 #define MP DDS_LIVELINESS_MANUAL_BY_PARTICIPANT
+#define MT DDS_LIVELINESS_MANUAL_BY_TOPIC
 CU_TheoryDataPoints(ddsc_liveliness, pmd_count) = {
-		CU_DataPoints(dds_liveliness_kind_t,  A,   A,  MP), /* liveliness kind */
-		CU_DataPoints(uint32_t,             200, 200, 200), /* lease duration */
-		CU_DataPoints(double,                 5,  10,   5),	/* delay (n times lease duration) */
+		CU_DataPoints(dds_liveliness_kind_t,  A,   A,  MP,  MT), /* liveliness kind */
+		CU_DataPoints(uint32_t,             200, 200, 200, 200), /* lease duration */
+		CU_DataPoints(double,                 5,  10,   5,   5), /* delay (n times lease duration) */
 };
-#undef A
+#undef MT
 #undef MP
+#undef A
 CU_Theory((dds_liveliness_kind_t kind, uint32_t ldur, double mult), ddsc_liveliness, pmd_count, .init = liveliness_init, .fini = liveliness_fini, .timeout = 30)
 {
 	dds_entity_t pub_topic;
@@ -150,7 +173,7 @@ CU_Theory((dds_liveliness_kind_t kind, uint32_t ldur, double mult), ddsc_livelin
 				 kind == 0 ? "A" : "MP", ldur, mult);
 
 	/* topics */
-	create_topic_name("ddsc_liveliness_test", g_topic_nr++, name, sizeof name);
+	create_topic_name("ddsc_liveliness_pmd_count", g_topic_nr++, name, sizeof name);
 	CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
 	CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
 
@@ -187,7 +210,7 @@ CU_Theory((dds_liveliness_kind_t kind, uint32_t ldur, double mult), ddsc_livelin
 
 	/* end-start should be mult - 1, but allow 1 pmd sample to be lost */
 	CU_ASSERT(end_seqno - start_seqno >= (kind == DDS_LIVELINESS_AUTOMATIC ? mult - 2 : 0))
-	if (kind == DDS_LIVELINESS_MANUAL_BY_PARTICIPANT)
+	if (kind != DDS_LIVELINESS_AUTOMATIC)
 		CU_ASSERT(get_pmd_seqno(g_pub_participant) - start_seqno < mult)
 
 	/* cleanup */
@@ -197,39 +220,42 @@ CU_Theory((dds_liveliness_kind_t kind, uint32_t ldur, double mult), ddsc_livelin
 	CU_ASSERT_EQUAL_FATAL(dds_delete(reader), DDS_RETCODE_OK);
 }
 
-/* FIXME: add DDS_LIVELINESS_MANUAL_BY_TOPIC */
+/**
+ * Test that the expected number of proxy writers expires (set to not-alive)
+ * after a certain delay for various combinations of writers with different
+ * liveliness kinds.
+ */
 CU_TheoryDataPoints(ddsc_liveliness, expire_liveliness_kinds) = {
-		CU_DataPoints(uint32_t,  200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200), /* lease duration */
-		CU_DataPoints(double,    0.3, 0.3, 0.3, 0.3,   2,   2,   2,   2,   2,   2,   2,   2,   2), /* delay (n times lease duration) */
-		CU_DataPoints(size_t,      1,   0,   2,   0,   1,   0,   1,   2,   0,   5,   0,  15,  15), /* number of writers with automatic liveliness */
-		CU_DataPoints(size_t,      1,   1,   2,   2,   1,   1,   0,   2,   2,   5,  10,   0,  15), /* number of writers with manual-by-participant liveliness */
+		CU_DataPoints(uint32_t,  200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200, 200), /* lease duration for initial test run (increased for each retry when test fails) */
+		CU_DataPoints(double,    0.3, 0.3, 0.3, 0.3, 0.3, 0.3,   2,   2,   2,   2,   2,   2,   2,   2,   2), /* delay (n times lease duration) */
+		CU_DataPoints(uint32_t,    1,   0,   2,   0,   1,   0,   0,   1,   1,   2,   0,   5,   0,  15,  15), /* number of writers with automatic liveliness */
+		CU_DataPoints(uint32_t,    1,   1,   2,   2,   0,   0,   0,   1,   0,   2,   2,   5,  10,   0,  15), /* number of writers with manual-by-participant liveliness */
+		CU_DataPoints(uint32_t,    1,   1,   2,   2,   1,   1,   1,   1,   0,   1,   1,   2,   5,   0,  10), /* number of writers with manual-by-topic liveliness */
 };
-CU_Theory((uint32_t ldur, double mult, size_t wr_cnt_auto, size_t wr_cnt_man_pp), ddsc_liveliness, expire_liveliness_kinds, .init = liveliness_init, .fini = liveliness_fini, .timeout = 60)
+CU_Theory((uint32_t ldur, double mult, uint32_t wr_cnt_auto, uint32_t wr_cnt_man_pp, uint32_t wr_cnt_man_tp), ddsc_liveliness, expire_liveliness_kinds, .init = liveliness_init, .fini = liveliness_fini, .timeout = 120)
 {
 	dds_entity_t pub_topic;
 	dds_entity_t sub_topic;
 	dds_entity_t reader;
 	dds_entity_t *writers;
-	dds_qos_t *rqos, *wqos_auto, *wqos_man_pp;
+	dds_qos_t *rqos, *wqos_auto, *wqos_man_pp, *wqos_man_tp;
 	dds_entity_t waitset;
 	dds_attach_t triggered;
 	struct dds_liveliness_changed_status lstatus;
-	uint32_t status;
-	size_t n, run = 1;
+	uint32_t status, n, run = 1, wr_cnt = wr_cnt_auto + wr_cnt_man_pp + wr_cnt_man_tp;
 	char name[100];
-	size_t wr_cnt = wr_cnt_auto + wr_cnt_man_pp;
 	dds_time_t tstart, t;
 	bool test_finished = false;
 
 	do
 	{
 		tstart = dds_time();
-		printf("%d.%06d running test: lease duration %d, delay %f, auto/manual-by-participant %zu/%zu\n",
+		printf("%d.%06d running test: lease duration %d, delay %f, auto/man-by-part/man-by-topic %u/%u/%u\n",
 					 (int32_t)(tstart / DDS_NSECS_IN_SEC), (int32_t)(tstart % DDS_NSECS_IN_SEC) / 1000,
-					 ldur, mult, wr_cnt_auto, wr_cnt_man_pp);
+					 ldur, mult, wr_cnt_auto, wr_cnt_man_pp, wr_cnt_man_tp);
 
 		/* topics */
-		create_topic_name("ddsc_liveliness_test", g_topic_nr++, name, sizeof name);
+		create_topic_name("ddsc_liveliness_expire_kinds", g_topic_nr++, name, sizeof name);
 		CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
 		CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
 
@@ -245,6 +271,8 @@ CU_Theory((uint32_t ldur, double mult, size_t wr_cnt_auto, size_t wr_cnt_man_pp)
 		dds_qset_liveliness(wqos_auto, DDS_LIVELINESS_AUTOMATIC, DDS_MSECS(ldur));
 		CU_ASSERT_FATAL((wqos_man_pp = dds_create_qos()) != NULL);
 		dds_qset_liveliness(wqos_man_pp, DDS_LIVELINESS_MANUAL_BY_PARTICIPANT, DDS_MSECS(ldur));
+		CU_ASSERT_FATAL((wqos_man_tp = dds_create_qos()) != NULL);
+		dds_qset_liveliness(wqos_man_tp, DDS_LIVELINESS_MANUAL_BY_TOPIC, DDS_MSECS(ldur));
 
 		CU_ASSERT_FATAL((waitset = dds_create_waitset(g_sub_participant)) > 0);
 		CU_ASSERT_EQUAL_FATAL(dds_waitset_attach(waitset, reader, reader), DDS_RETCODE_OK);
@@ -252,17 +280,20 @@ CU_Theory((uint32_t ldur, double mult, size_t wr_cnt_auto, size_t wr_cnt_man_pp)
 		writers = dds_alloc(wr_cnt * sizeof(dds_entity_t));
 		for (n = 0; n < wr_cnt; n++)
 		{
-			CU_ASSERT_FATAL((writers[n] = dds_create_writer(g_pub_participant, pub_topic, n < wr_cnt_auto ? wqos_auto : wqos_man_pp, NULL)) > 0);
+			dds_qos_t *wqos;
+			wqos = n < wr_cnt_auto ? wqos_auto : (n < (wr_cnt_auto + wr_cnt_man_pp) ? wqos_man_pp : wqos_man_tp);
+			CU_ASSERT_FATAL((writers[n] = dds_create_writer(g_pub_participant, pub_topic, wqos, NULL)) > 0);
 			CU_ASSERT_EQUAL_FATAL(dds_waitset_wait(waitset, &triggered, 1, DDS_SECS(5)), 1);
 			CU_ASSERT_EQUAL_FATAL(dds_take_status(reader, &status, DDS_LIVELINESS_CHANGED_STATUS), DDS_RETCODE_OK);
 		}
 		dds_delete_qos(wqos_auto);
 		dds_delete_qos(wqos_man_pp);
+		dds_delete_qos(wqos_man_tp);
 
 		t = dds_time();
 		if (t - tstart > DDS_MSECS(0.5 * ldur))
 		{
-			ldur *= 10;
+			ldur *= 10 / (run + 1);
 			printf("%d.%06d failed to create writers in time\n",
 						 (int32_t)(t / DDS_NSECS_IN_SEC), (int32_t)(t % DDS_NSECS_IN_SEC) / 1000);
 		}
@@ -274,7 +305,7 @@ CU_Theory((uint32_t ldur, double mult, size_t wr_cnt_auto, size_t wr_cnt_man_pp)
 			CU_ASSERT_EQUAL_FATAL(lstatus.alive_count, wr_cnt);
 
 			dds_time_t tstop = tstart + DDS_MSECS((dds_duration_t)(mult * ldur));
-			size_t stopped = 0;
+			uint32_t stopped = 0;
 			do
 			{
 				dds_duration_t w = tstop - dds_time();
@@ -283,13 +314,13 @@ CU_Theory((uint32_t ldur, double mult, size_t wr_cnt_auto, size_t wr_cnt_man_pp)
 				stopped += (uint32_t)lstatus.not_alive_count_change;
 			} while (dds_time() < tstop);
 			t = dds_time();
-			printf("%d.%06d writers stopped: %zu\n",
+			printf("%d.%06d writers stopped: %u\n",
 						 (int32_t)(t / DDS_NSECS_IN_SEC), (int32_t)(t % DDS_NSECS_IN_SEC) / 1000, stopped);
 
-			size_t exp_stopped = mult < 1 ? 0 : wr_cnt_man_pp;
+			size_t exp_stopped = mult < 1 ? 0 : (wr_cnt_man_pp + wr_cnt_man_tp);
 			if (stopped != exp_stopped)
 			{
-				ldur *= 10;
+				ldur *= 10 / (run + 1);
 				printf("%d.%06d incorrect number of stopped writers\n",
 							 (int32_t)(t / DDS_NSECS_IN_SEC), (int32_t)(t % DDS_NSECS_IN_SEC) / 1000);
 			}
@@ -315,7 +346,7 @@ CU_Theory((uint32_t ldur, double mult, size_t wr_cnt_auto, size_t wr_cnt_man_pp)
 
 		if (!test_finished)
 		{
-			if (run++ > 2)
+			if (++run > 3)
 			{
 				printf("%d.%06d run limit reached, test failed\n", (int32_t)(tstart / DDS_NSECS_IN_SEC), (int32_t)(tstart % DDS_NSECS_IN_SEC) / 1000);
 				CU_FAIL_FATAL("Run limit reached");
@@ -354,6 +385,10 @@ static void add_and_check_writer(dds_liveliness_kind_t kind, dds_duration_t ldur
 	CU_ASSERT_EQUAL_FATAL(dds_delete(waitset), DDS_RETCODE_OK);
 }
 
+/**
+ * Test that the correct PMD interval is set for the participant
+ * based on the lease duration of the writers.
+ */
 #define MAX_WRITERS 10
 CU_Test(ddsc_liveliness, lease_duration, .init = liveliness_init, .fini = liveliness_fini)
 {
@@ -361,7 +396,7 @@ CU_Test(ddsc_liveliness, lease_duration, .init = liveliness_init, .fini = liveli
 	dds_entity_t sub_topic;
 	dds_entity_t reader;
 	dds_entity_t writers[MAX_WRITERS];
-	size_t wr_cnt = 0;
+	uint32_t wr_cnt = 0;
 	char name[100];
 	dds_qos_t *rqos;
 	uint32_t n;
@@ -397,6 +432,9 @@ CU_Test(ddsc_liveliness, lease_duration, .init = liveliness_init, .fini = liveli
 	add_and_check_writer(DDS_LIVELINESS_MANUAL_BY_PARTICIPANT, DDS_MSECS(100), &writers[wr_cnt++], pub_topic, reader);
 	CU_ASSERT_EQUAL_FATAL(get_pmd_interval(g_pub_participant), DDS_MSECS(500));
 
+	add_and_check_writer(DDS_LIVELINESS_MANUAL_BY_TOPIC, DDS_MSECS(100), &writers[wr_cnt++], pub_topic, reader);
+	CU_ASSERT_EQUAL_FATAL(get_pmd_interval(g_pub_participant), DDS_MSECS(500));
+
 	/* cleanup */
 	for (n = 0; n < wr_cnt; n++)
 		CU_ASSERT_EQUAL_FATAL(dds_delete(writers[n]), DDS_RETCODE_OK);
@@ -406,6 +444,9 @@ CU_Test(ddsc_liveliness, lease_duration, .init = liveliness_init, .fini = liveli
 }
 #undef MAX_WRITERS
 
+/**
+ * Check that the correct lease duration is set in the matched
+ * publications in the readers. */
 CU_Test(ddsc_liveliness, lease_duration_pwr, .init = liveliness_init, .fini = liveliness_fini)
 {
 	dds_entity_t pub_topic;
@@ -465,6 +506,12 @@ CU_Test(ddsc_liveliness, lease_duration_pwr, .init = liveliness_init, .fini = li
 	CU_ASSERT_EQUAL_FATAL(dds_delete(reader), DDS_RETCODE_OK);
 }
 
+/**
+ * Create a relative large number of writers with liveliness kinds automatic and
+ * manual-by-participant and with decreasing lease duration, and check that all
+ * writers become alive. During the writer creation loop, every third writer
+ * is deleted immediately after creating.
+ */
 #define MAX_WRITERS 100
 CU_Test(ddsc_liveliness, create_delete_writer_stress, .init = liveliness_init, .fini = liveliness_fini)
 {
@@ -475,11 +522,11 @@ CU_Test(ddsc_liveliness, create_delete_writer_stress, .init = liveliness_init, .
 	dds_entity_t waitset;
 	dds_qos_t *wqos;
 	struct dds_liveliness_changed_status lstatus;
-	size_t wr_cnt = 0;
+	uint32_t wr_cnt = 0;
 	char name[100];
 	dds_qos_t *rqos;
 	dds_attach_t triggered;
-	uint32_t n, status;
+	uint32_t n;
 	Space_Type1 sample = { 0, 0, 0 };
 
 	/* topics */
@@ -501,12 +548,11 @@ CU_Test(ddsc_liveliness, create_delete_writer_stress, .init = liveliness_init, .
 	dds_qset_liveliness(wqos, DDS_LIVELINESS_MANUAL_BY_PARTICIPANT, DDS_MSECS (500));
 	CU_ASSERT_FATAL((writers[0] = dds_create_writer(g_pub_participant, pub_topic, wqos, NULL)) > 0);
 	CU_ASSERT_EQUAL_FATAL(dds_waitset_wait(waitset, &triggered, 1, DDS_MSECS(1000)), 1);
-	CU_ASSERT_EQUAL_FATAL(dds_take_status(reader, &status, DDS_LIVELINESS_CHANGED_STATUS), DDS_RETCODE_OK);
 
 	/* create writers */
 	for (n = 1; n < MAX_WRITERS; n++)
 	{
-		dds_qset_liveliness(wqos, n % 1 ? DDS_LIVELINESS_AUTOMATIC : DDS_LIVELINESS_MANUAL_BY_PARTICIPANT, DDS_MSECS (500 - n));
+		dds_qset_liveliness(wqos, n % 2 ? DDS_LIVELINESS_AUTOMATIC : DDS_LIVELINESS_MANUAL_BY_PARTICIPANT, DDS_MSECS (n % 3 ? 500 + n : 500 - n));
 		CU_ASSERT_FATAL((writers[n] = dds_create_writer(g_pub_participant, pub_topic, wqos, NULL)) > 0);
 		dds_write (writers[n], &sample);
 		if (n % 3 == 2)
@@ -537,6 +583,9 @@ CU_Test(ddsc_liveliness, create_delete_writer_stress, .init = liveliness_init, .
 }
 #undef MAX_WRITERS
 
+/**
+ * Check the counts in liveliness_changed_status result.
+ */
 CU_Test(ddsc_liveliness, status_counts, .init = liveliness_init, .fini = liveliness_fini)
 {
 	dds_entity_t pub_topic;
@@ -547,7 +596,6 @@ CU_Test(ddsc_liveliness, status_counts, .init = liveliness_init, .fini = livelin
 	dds_qos_t *rqos;
 	dds_qos_t *wqos;
 	dds_attach_t triggered;
-	uint32_t status = 0;
 	struct dds_liveliness_changed_status lstatus;
 	struct dds_subscription_matched_status sstatus;
 	char name[100];
@@ -576,7 +624,6 @@ CU_Test(ddsc_liveliness, status_counts, .init = liveliness_init, .fini = livelin
 
 	/* wait for writer to be alive */
 	CU_ASSERT_EQUAL_FATAL(dds_waitset_wait(waitset, &triggered, 1, DDS_SECS(5)), 1);
-	CU_ASSERT_EQUAL_FATAL(dds_take_status(reader, &status, DDS_LIVELINESS_CHANGED_STATUS), DDS_RETCODE_OK);
 
 	/* check status counts before proxy writer is expired */
 	dds_get_liveliness_changed_status(reader, &lstatus);
@@ -587,7 +634,6 @@ CU_Test(ddsc_liveliness, status_counts, .init = liveliness_init, .fini = livelin
 	/* sleep for more than lease duration, writer should be set not-alive but subscription still matched */
 	dds_sleepfor(ldur + DDS_MSECS(100));
 	CU_ASSERT_EQUAL_FATAL(dds_waitset_wait(waitset, &triggered, 1, DDS_SECS(5)), 1);
-	CU_ASSERT_EQUAL_FATAL(dds_take_status(reader, &status, DDS_LIVELINESS_CHANGED_STATUS), DDS_RETCODE_OK);
 
 	dds_get_liveliness_changed_status(reader, &lstatus);
 	CU_ASSERT_EQUAL_FATAL(lstatus.alive_count, 0);
@@ -597,7 +643,6 @@ CU_Test(ddsc_liveliness, status_counts, .init = liveliness_init, .fini = livelin
 	/* write sample and re-check status counts */
 	dds_write (writer, &sample);
 	CU_ASSERT_EQUAL_FATAL(dds_waitset_wait(waitset, &triggered, 1, DDS_SECS(5)), 1);
-	CU_ASSERT_EQUAL_FATAL(dds_take_status(reader, &status, DDS_LIVELINESS_CHANGED_STATUS), DDS_RETCODE_OK);
 
 	dds_get_liveliness_changed_status(reader, &lstatus);
 	CU_ASSERT_EQUAL_FATAL(lstatus.alive_count, 1);
@@ -612,3 +657,96 @@ CU_Test(ddsc_liveliness, status_counts, .init = liveliness_init, .fini = livelin
 	CU_ASSERT_EQUAL_FATAL(dds_delete(sub_topic), DDS_RETCODE_OK);
 	CU_ASSERT_EQUAL_FATAL(dds_delete(pub_topic), DDS_RETCODE_OK);
 }
+
+/**
+ * Test that dds_assert_liveliness works as expected for liveliness
+ * kinds manual-by-participant and manual-by-topic.
+ */
+#define MAX_WRITERS 100
+CU_TheoryDataPoints(ddsc_liveliness, assert_liveliness) = {
+		CU_DataPoints(uint32_t,      1, 0, 0, 1), /* number of writers with automatic liveliness */
+		CU_DataPoints(uint32_t,      1, 1, 0, 0), /* number of writers with manual-by-participant liveliness */
+		CU_DataPoints(uint32_t,      1, 1, 1, 2), /* number of writers with manual-by-topic liveliness */
+};
+CU_Theory((uint32_t wr_cnt_auto, uint32_t wr_cnt_man_pp, uint32_t wr_cnt_man_tp), ddsc_liveliness, assert_liveliness, .init = liveliness_init, .fini = liveliness_fini, .timeout=30)
+{
+	dds_entity_t pub_topic;
+	dds_entity_t sub_topic;
+	dds_entity_t reader;
+	dds_entity_t writers[MAX_WRITERS];
+	dds_qos_t *rqos;
+	struct dds_liveliness_changed_status lstatus;
+	char name[100];
+	dds_duration_t ldur = DDS_MSECS (300);
+	uint32_t wr_cnt = 0;
+	dds_time_t tstop;
+	uint32_t stopped;
+
+	assert (wr_cnt_auto + wr_cnt_man_pp + wr_cnt_man_tp < MAX_WRITERS);
+	printf("running test assert_liveliness: auto/man-by-part/man-by-topic %u/%u/%u\n", wr_cnt_auto, wr_cnt_man_pp, wr_cnt_man_tp);
+
+	/* topics */
+	create_topic_name("ddsc_liveliness_assert", g_topic_nr++, name, sizeof name);
+	CU_ASSERT_FATAL((pub_topic = dds_create_topic(g_pub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
+	CU_ASSERT_FATAL((sub_topic = dds_create_topic(g_sub_participant, &Space_Type1_desc, name, NULL, NULL)) > 0);
+
+	/* reader */
+	CU_ASSERT_FATAL((rqos = dds_create_qos()) != NULL);
+	dds_qset_liveliness(rqos, DDS_LIVELINESS_AUTOMATIC, DDS_INFINITY);
+	CU_ASSERT_FATAL((reader = dds_create_reader(g_sub_participant, sub_topic, rqos, NULL)) > 0);
+	dds_delete_qos(rqos);
+	CU_ASSERT_EQUAL_FATAL(dds_set_status_mask(reader, DDS_LIVELINESS_CHANGED_STATUS), DDS_RETCODE_OK);
+
+	/* writers */
+	for (size_t n = 0; n < wr_cnt_auto; n++)
+		add_and_check_writer(DDS_LIVELINESS_AUTOMATIC, ldur, &writers[wr_cnt++], pub_topic, reader);
+	for (size_t n = 0; n < wr_cnt_man_pp; n++)
+		add_and_check_writer(DDS_LIVELINESS_MANUAL_BY_PARTICIPANT, ldur, &writers[wr_cnt++], pub_topic, reader);
+	for (size_t n = 0; n < wr_cnt_man_tp; n++)
+		add_and_check_writer(DDS_LIVELINESS_MANUAL_BY_TOPIC, ldur, &writers[wr_cnt++], pub_topic, reader);
+
+	/* check status counts before proxy writer is expired */
+	dds_get_liveliness_changed_status(reader, &lstatus);
+	CU_ASSERT_EQUAL_FATAL(lstatus.alive_count, wr_cnt_auto + wr_cnt_man_pp + wr_cnt_man_tp);
+
+	/* delay for more than lease duration and assert liveliness on writers:
+	   all writers (including man-by-pp) should be kept alive */
+	tstop = dds_time() + 4 * ldur / 3;
+	stopped = 0;
+	do
+	{
+		for (size_t n = wr_cnt - wr_cnt_man_tp; n < wr_cnt; n++)
+			dds_assert_liveliness (writers[n]);
+		CU_ASSERT_EQUAL_FATAL(dds_get_liveliness_changed_status(reader, &lstatus), DDS_RETCODE_OK);
+		stopped += (uint32_t)lstatus.not_alive_count_change;
+		dds_sleepfor (DDS_MSECS(50));
+	} while (dds_time() < tstop);
+	CU_ASSERT_EQUAL_FATAL(stopped, 0);
+	dds_get_liveliness_changed_status(reader, &lstatus);
+	CU_ASSERT_EQUAL_FATAL(lstatus.alive_count, wr_cnt_auto + wr_cnt_man_pp + wr_cnt_man_tp);
+
+	/* delay for more than lease duration and assert liveliness on participant:
+	   writers with liveliness man-by-pp should be kept alive, man-by-topic writers
+	   should stop */
+	tstop = dds_time() + 4 * ldur / 3;
+	stopped = 0;
+	do
+	{
+		dds_assert_liveliness (g_pub_participant);
+		CU_ASSERT_EQUAL_FATAL(dds_get_liveliness_changed_status(reader, &lstatus), DDS_RETCODE_OK);
+		stopped += (uint32_t)lstatus.not_alive_count_change;
+		dds_sleepfor (DDS_MSECS(50));
+	} while (dds_time() < tstop);
+	CU_ASSERT_EQUAL_FATAL(stopped, wr_cnt_man_tp);
+	dds_get_liveliness_changed_status(reader, &lstatus);
+	printf("writers alive_count: %d\n", lstatus.alive_count);
+	CU_ASSERT_EQUAL_FATAL(lstatus.alive_count, wr_cnt_auto + wr_cnt_man_pp);
+
+	/* cleanup */
+	CU_ASSERT_EQUAL_FATAL(dds_delete(reader), DDS_RETCODE_OK);
+	for (size_t n = 0; n < wr_cnt; n++)
+		CU_ASSERT_EQUAL_FATAL(dds_delete(writers[n]), DDS_RETCODE_OK);
+	CU_ASSERT_EQUAL_FATAL(dds_delete(sub_topic), DDS_RETCODE_OK);
+	CU_ASSERT_EQUAL_FATAL(dds_delete(pub_topic), DDS_RETCODE_OK);
+}
+#undef MAX_WRITERS
diff --git a/src/core/ddsi/include/dds/ddsi/q_entity.h b/src/core/ddsi/include/dds/ddsi/q_entity.h
index b6b0877..12e62dd 100644
--- a/src/core/ddsi/include/dds/ddsi/q_entity.h
+++ b/src/core/ddsi/include/dds/ddsi/q_entity.h
@@ -323,6 +323,7 @@ struct proxy_participant
   unsigned is_ddsi2_pp: 1; /* if this is the federation-leader on the remote node */
   unsigned minimal_bes_mode: 1;
   unsigned lease_expired: 1;
+  unsigned deleting: 1;
   unsigned proxypp_have_spdp: 1;
   unsigned proxypp_have_cm: 1;
   unsigned owns_lease: 1;
@@ -369,7 +370,7 @@ struct proxy_writer {
   unsigned deliver_synchronously: 1; /* iff 1, delivery happens straight from receive thread for non-historical data; else through delivery queue "dqueue" */
   unsigned have_seen_heartbeat: 1; /* iff 1, we have received at least on heartbeat from this proxy writer */
   unsigned local_matching_inprogress: 1; /* iff 1, we are still busy matching local readers; this is so we don't deliver incoming data to some but not all readers initially */
-  unsigned alive: 1; /* iff 1, the proxy writer is alive (lease for this proxy writer is not expired) */
+  unsigned alive: 1; /* iff 1, the proxy writer is alive (lease for this proxy writer is not expired); field may be modified only when holding both pwr->e.lock and pwr->c.proxypp->e.lock */
 #ifdef DDSI_INCLUDE_SSM
   unsigned supports_ssm: 1; /* iff 1, this proxy writer supports SSM */
 #endif
@@ -645,14 +646,14 @@ int new_proxy_reader (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
    reader or writer. Actual deletion is scheduled in the future, when
    no outstanding references may still exist (determined by checking
    thread progress, &c.). */
-int delete_proxy_writer (struct q_globals *gv, const struct ddsi_guid *guid, nn_wctime_t timestamp, int isimplicit, bool proxypp_locked);
+int delete_proxy_writer (struct q_globals *gv, const struct ddsi_guid *guid, nn_wctime_t timestamp, int isimplicit);
 int delete_proxy_reader (struct q_globals *gv, const struct ddsi_guid *guid, nn_wctime_t timestamp, int isimplicit);
 
 void update_proxy_reader (struct proxy_reader *prd, seqno_t seq, struct addrset *as, const struct dds_qos *xqos, nn_wctime_t timestamp);
 void update_proxy_writer (struct proxy_writer *pwr, seqno_t seq, struct addrset *as, const struct dds_qos *xqos, nn_wctime_t timestamp);
 
-int proxy_writer_set_alive_locked (struct q_globals *gv, struct proxy_writer *pwr, bool alive);
-int proxy_writer_set_alive_guid (struct q_globals *gv, const struct ddsi_guid *guid, bool alive);
+int proxy_writer_set_alive (struct proxy_writer *pwr);
+int proxy_writer_set_notalive (struct proxy_writer *pwr);
 
 int new_proxy_group (const struct ddsi_guid *guid, const char *name, const struct dds_qos *xqos, nn_wctime_t timestamp);
 void delete_proxy_group (struct ephash *guid_hash, const struct ddsi_guid *guid, nn_wctime_t timestamp, int isimplicit);
@@ -661,6 +662,8 @@ void delete_proxy_group (struct ephash *guid_hash, const struct ddsi_guid *guid,
    rebuild them all (which only makes sense after previously having emptied them all). */
 void rebuild_or_clear_writer_addrsets(struct q_globals *gv, int rebuild);
 
+void reader_drop_connection (const struct ddsi_guid *rd_guid, const struct proxy_writer *pwr, bool unmatch);
+
 void local_reader_ary_setfastpath_ok (struct local_reader_ary *x, bool fastpath_ok);
 
 struct ddsi_writer_info;
diff --git a/src/core/ddsi/include/dds/ddsi/q_transmit.h b/src/core/ddsi/include/dds/ddsi/q_transmit.h
index c7899e6..b88b999 100644
--- a/src/core/ddsi/include/dds/ddsi/q_transmit.h
+++ b/src/core/ddsi/include/dds/ddsi/q_transmit.h
@@ -42,7 +42,8 @@ int write_sample_nogc_notk (struct thread_state1 * const ts1, struct nn_xpack *x
 /* When calling the following functions, wr->lock must be held */
 dds_return_t create_fragment_message (struct writer *wr, seqno_t seq, const struct nn_plist *plist, struct ddsi_serdata *serdata, unsigned fragnum, struct proxy_reader *prd,struct nn_xmsg **msg, int isnew);
 int enqueue_sample_wrlock_held (struct writer *wr, seqno_t seq, const struct nn_plist *plist, struct ddsi_serdata *serdata, struct proxy_reader *prd, int isnew);
-void add_Heartbeat (struct nn_xmsg *msg, struct writer *wr, const struct whc_state *whcst, int hbansreq, ddsi_entityid_t dst, int issync);
+void add_Heartbeat (struct nn_xmsg *msg, struct writer *wr, const struct whc_state *whcst, int hbansreq, int hbliveliness, ddsi_entityid_t dst, int issync);
+dds_return_t write_hb_liveliness (struct q_globals * const gv, struct ddsi_guid *wr_guid, struct nn_xpack *xp);
 
 #if defined (__cplusplus)
 }
diff --git a/src/core/ddsi/src/q_ddsi_discovery.c b/src/core/ddsi/src/q_ddsi_discovery.c
index b53b35b..f9f13c2 100644
--- a/src/core/ddsi/src/q_ddsi_discovery.c
+++ b/src/core/ddsi/src/q_ddsi_discovery.c
@@ -1357,13 +1357,9 @@ static void handle_SEDP_dead (const struct receiver_state *rst, nn_plist_t *data
   }
   GVLOGDISC (" "PGUIDFMT, PGUID (datap->endpoint_guid));
   if (is_writer_entityid (datap->endpoint_guid.entityid))
-  {
-    res = delete_proxy_writer (gv, &datap->endpoint_guid, timestamp, 0, false);
-  }
+    res = delete_proxy_writer (gv, &datap->endpoint_guid, timestamp, 0);
   else
-  {
     res = delete_proxy_reader (gv, &datap->endpoint_guid, timestamp, 0);
-  }
   GVLOGDISC (" %s\n", (res < 0) ? " unknown" : " delete");
 }
 
diff --git a/src/core/ddsi/src/q_entity.c b/src/core/ddsi/src/q_entity.c
index f9adc0b..475d690 100644
--- a/src/core/ddsi/src/q_entity.c
+++ b/src/core/ddsi/src/q_entity.c
@@ -1488,7 +1488,7 @@ static void writer_drop_local_connection (const struct ddsi_guid *wr_guid, struc
   }
 }
 
-static void reader_drop_connection (const struct ddsi_guid *rd_guid, const struct proxy_writer *pwr, bool unmatch)
+void reader_drop_connection (const struct ddsi_guid *rd_guid, const struct proxy_writer *pwr, bool unmatch)
 {
   struct reader *rd;
   if ((rd = ephash_lookup_reader_guid (pwr->e.gv->guid_hash, rd_guid)) != NULL)
@@ -3619,16 +3619,20 @@ void proxy_participant_reassign_lease (struct proxy_participant *proxypp, struct
 
 static void proxy_participant_replace_minl (struct proxy_participant *proxypp, bool manbypp, struct lease *lnew)
 {
+  /* By loading/storing the pointer atomically, we ensure we always
+     read a valid (or once valid) lease. By delaying freeing the lease
+     through the garbage collector, we ensure whatever lease update
+     occurs in parallel completes before the memory is released. */
   const nn_etime_t never = { T_NEVER };
   struct gcreq *gcreq = gcreq_new (proxypp->e.gv->gcreq_queue, gc_proxy_participant_lease);
-  struct lease *lease_old = (struct lease *) ddsrt_atomic_ldvoidp (manbypp ? &proxypp->minl_man : &proxypp->minl_auto);
-  lease_renew (lease_old, never);
-  gcreq->arg = (void *) lease_old;
+  struct lease *lease_old = ddsrt_atomic_ldvoidp (manbypp ? &proxypp->minl_man : &proxypp->minl_auto);
+  lease_renew (lease_old, never); /* ensures lease will not expire while it is replaced */
+  gcreq->arg = lease_old;
   gcreq_enqueue (gcreq);
-  ddsrt_atomic_stvoidp (manbypp ? &proxypp->minl_man : &proxypp->minl_auto, (void *) lnew);
+  ddsrt_atomic_stvoidp (manbypp ? &proxypp->minl_man : &proxypp->minl_auto, lnew);
 }
 
-static void proxy_participant_add_pwr_lease (struct proxy_participant * proxypp, const struct proxy_writer * pwr)
+static void proxy_participant_add_pwr_lease_locked (struct proxy_participant * proxypp, const struct proxy_writer * pwr)
 {
   struct lease *minl_prev;
   struct lease *minl_new;
@@ -3637,7 +3641,6 @@ static void proxy_participant_add_pwr_lease (struct proxy_participant * proxypp,
 
   assert (pwr->lease != NULL);
   manbypp = (pwr->c.xqos->liveliness.kind == DDS_LIVELINESS_MANUAL_BY_PARTICIPANT);
-  ddsrt_mutex_lock (&proxypp->e.lock);
   lh = manbypp ? &proxypp->leaseheap_man : &proxypp->leaseheap_auto;
   minl_prev = ddsrt_fibheap_min (&lease_fhdef_proxypp, lh);
   ddsrt_fibheap_insert (&lease_fhdef_proxypp, lh, pwr->lease);
@@ -3647,10 +3650,11 @@ static void proxy_participant_add_pwr_lease (struct proxy_participant * proxypp,
   {
     nn_etime_t texp = add_duration_to_etime (now_et (), minl_new->tdur);
     struct lease *lnew = lease_new (texp, minl_new->tdur, minl_new->entity);
-    if (manbypp && minl_prev == NULL)
+    if (minl_prev == NULL)
     {
+      assert (manbypp);
       assert (ddsrt_atomic_ldvoidp (&proxypp->minl_man) == NULL);
-      ddsrt_atomic_stvoidp (&proxypp->minl_man, (void *) lnew);
+      ddsrt_atomic_stvoidp (&proxypp->minl_man, lnew);
     }
     else
     {
@@ -3658,7 +3662,6 @@ static void proxy_participant_add_pwr_lease (struct proxy_participant * proxypp,
     }
     lease_register (lnew);
   }
-  ddsrt_mutex_unlock (&proxypp->e.lock);
 }
 
 static void proxy_participant_remove_pwr_lease_locked (struct proxy_participant * proxypp, struct proxy_writer * pwr)
@@ -3684,25 +3687,14 @@ static void proxy_participant_remove_pwr_lease_locked (struct proxy_participant
       proxy_participant_replace_minl (proxypp, manbypp, lnew);
       lease_register (lnew);
     }
-    else if (manbypp)
-    {
-      proxy_participant_replace_minl (proxypp, manbypp, NULL);
-    }
     else
     {
-      /* minl should not be null for leaseheap_auto because proxypp's lease is in */
-      assert (false);
+      assert (manbypp);
+      proxy_participant_replace_minl (proxypp, manbypp, NULL);
     }
   }
 }
 
-static void proxy_participant_remove_pwr_lease (struct proxy_participant * proxypp, struct proxy_writer * pwr)
-{
-  ddsrt_mutex_lock (&proxypp->e.lock);
-  proxy_participant_remove_pwr_lease_locked (proxypp, pwr);
-  ddsrt_mutex_unlock (&proxypp->e.lock);
-}
-
 void new_proxy_participant
 (
   struct q_globals *gv,
@@ -3736,6 +3728,7 @@ void new_proxy_participant
   entity_common_init (&proxypp->e, gv, ppguid, "", EK_PROXY_PARTICIPANT, timestamp, vendor, false);
   proxypp->refc = 1;
   proxypp->lease_expired = 0;
+  proxypp->deleting = 0;
   proxypp->vendor = vendor;
   proxypp->bes = bes;
   proxypp->prismtech_bes = prismtech_bes;
@@ -3789,8 +3782,11 @@ void new_proxy_participant
          and uses the shortest duration for proxypp and all its pwr's (with automatic liveliness) */
       ddsrt_fibheap_insert (&lease_fhdef_proxypp, &proxypp->leaseheap_auto, proxypp->lease);
 
-      /* Set the shortest lease for auto liveliness: clone proxypp's lease (as there are no pwr's
-          at this point, this is the shortest lease) */
+      /* Set the shortest lease for auto liveliness: clone proxypp's lease and store the clone in
+         proxypp->minl_auto. As there are no pwr's at this point, the proxy pp's lease is the
+         shortest lease. When a pwr with a shorter is added, the lease in minl_auto is replaced
+         by the lease from the proxy writer in proxy_participant_add_pwr_lease_locked. This old shortest
+         lease is freed, so that's why we need a clone and not the proxypp's lease in the heap.  */
       ddsrt_atomic_stvoidp (&proxypp->minl_auto, (void *) lease_clone (proxypp->lease));
       ddsrt_atomic_stvoidp (&proxypp->minl_man, NULL);
     }
@@ -3948,9 +3944,14 @@ int update_proxy_participant_plist (struct proxy_participant *proxypp, seqno_t s
   return 0;
 }
 
-static void ref_proxy_participant (struct proxy_participant *proxypp, struct proxy_endpoint_common *c)
+static int ref_proxy_participant (struct proxy_participant *proxypp, struct proxy_endpoint_common *c)
 {
   ddsrt_mutex_lock (&proxypp->e.lock);
+  if (proxypp->deleting)
+  {
+    ddsrt_mutex_unlock (&proxypp->e.lock);
+    return DDS_RETCODE_PRECONDITION_NOT_MET;
+  }
   c->proxypp = proxypp;
   proxypp->refc++;
 
@@ -3962,6 +3963,8 @@ static void ref_proxy_participant (struct proxy_participant *proxypp, struct pro
   }
   proxypp->endpoints = c;
   ddsrt_mutex_unlock (&proxypp->e.lock);
+
+  return DDS_RETCODE_OK;
 }
 
 static void unref_proxy_participant (struct proxy_participant *proxypp, struct proxy_endpoint_common *c)
@@ -4070,8 +4073,9 @@ static void delete_or_detach_dependent_pp (struct proxy_participant *p, struct p
 
 static void delete_ppt (struct proxy_participant *proxypp, nn_wctime_t timestamp, int isimplicit)
 {
-  struct proxy_endpoint_common * c;
-  int ret;
+  ddsi_entityid_t *eps;
+  ddsi_guid_t ep_guid;
+  uint32_t ep_count = 0;
 
   /* if any proxy participants depend on this participant, delete them */
   ELOGDISC (proxypp, "delete_ppt("PGUIDFMT") - deleting dependent proxy participants\n", PGUID (proxypp->e.guid));
@@ -4084,31 +4088,38 @@ static void delete_ppt (struct proxy_participant *proxypp, nn_wctime_t timestamp
     ephash_enum_proxy_participant_fini (&est);
   }
 
-  /* delete_proxy_{reader,writer} merely schedules the actual delete
-     operation, so we can hold the lock -- at least, for now. */
-
   ddsrt_mutex_lock (&proxypp->e.lock);
+  proxypp->deleting = 1;
   if (isimplicit)
     proxypp->lease_expired = 1;
 
-  ELOGDISC (proxypp, "delete_ppt("PGUIDFMT") - deleting endpoints\n", PGUID (proxypp->e.guid));
-  c = proxypp->endpoints;
-  while (c)
+  /* Get snapshot of endpoints list so that we can release proxypp->e.lock
+     Pwrs/prds may be deleted during the iteration over the entities,
+     but resolving the guid will fail for these entities and the our
+     call to delete_proxy_writer/reader returns. */
   {
-    struct entity_common *e = entity_common_from_proxy_endpoint_common (c);
-    if (is_writer_entityid (e->guid.entityid))
+    eps = ddsrt_malloc (proxypp->refc * sizeof(ddsi_entityid_t));
+    struct proxy_endpoint_common *cep = proxypp->endpoints;
+    while (cep)
     {
-      ret = delete_proxy_writer (proxypp->e.gv, &e->guid, timestamp, isimplicit, true);
+      const struct entity_common *entc = entity_common_from_proxy_endpoint_common (cep);
+      eps[ep_count++] = entc->guid.entityid;
+      cep = cep->next_ep;
     }
-    else
-    {
-      ret = delete_proxy_reader (proxypp->e.gv, &e->guid, timestamp, isimplicit);
-    }
-    (void) ret;
-    c = c->next_ep;
   }
   ddsrt_mutex_unlock (&proxypp->e.lock);
 
+  ELOGDISC (proxypp, "delete_ppt("PGUIDFMT") - deleting endpoints\n", PGUID (proxypp->e.guid));
+  ep_guid.prefix = proxypp->e.guid.prefix;
+  for (uint32_t n = 0; n < ep_count; n++)
+  {
+    ep_guid.entityid = eps[n];
+    if (is_writer_entityid (ep_guid.entityid))
+      delete_proxy_writer (proxypp->e.gv, &ep_guid, timestamp, isimplicit);
+    else
+      delete_proxy_reader (proxypp->e.gv, &ep_guid, timestamp, isimplicit);
+  }
+  ddsrt_free (eps);
   gcreq_proxy_participant (proxypp);
 }
 
@@ -4185,9 +4196,10 @@ uint64_t get_entity_instance_id (const struct q_globals *gv, const struct ddsi_g
 
 /* PROXY-ENDPOINT --------------------------------------------------- */
 
-static void proxy_endpoint_common_init (struct entity_common *e, struct proxy_endpoint_common *c, enum entity_kind kind, const struct ddsi_guid *guid, nn_wctime_t tcreate, seqno_t seq, struct proxy_participant *proxypp, struct addrset *as, const nn_plist_t *plist)
+static int proxy_endpoint_common_init (struct entity_common *e, struct proxy_endpoint_common *c, enum entity_kind kind, const struct ddsi_guid *guid, nn_wctime_t tcreate, seqno_t seq, struct proxy_participant *proxypp, struct addrset *as, const nn_plist_t *plist)
 {
   const char *name;
+  int ret;
 
   if (is_builtin_entityid (guid->entityid, proxypp->vendor))
     assert ((plist->qos.present & (QP_TOPIC_NAME | QP_TYPE_NAME)) == 0);
@@ -4206,7 +4218,16 @@ static void proxy_endpoint_common_init (struct entity_common *e, struct proxy_en
   else
     memset (&c->group_guid, 0, sizeof (c->group_guid));
 
-  ref_proxy_participant (proxypp, c);
+  if ((ret = ref_proxy_participant (proxypp, c)) != DDS_RETCODE_OK)
+  {
+    nn_xqos_fini (c->xqos);
+    ddsrt_free (c->xqos);
+    unref_addrset (c->as);
+    entity_common_fini (e);
+    return ret;
+  }
+
+  return DDS_RETCODE_OK;
 }
 
 static void proxy_endpoint_common_fini (struct entity_common *e, struct proxy_endpoint_common *c)
@@ -4226,6 +4247,7 @@ int new_proxy_writer (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
   struct proxy_writer *pwr;
   int isreliable;
   nn_mtime_t tnow = now_mt ();
+  int ret;
 
   assert (is_writer_entityid (guid->entityid));
   assert (ephash_lookup_proxy_writer_guid (gv->guid_hash, guid) == NULL);
@@ -4237,7 +4259,11 @@ int new_proxy_writer (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
   }
 
   pwr = ddsrt_malloc (sizeof (*pwr));
-  proxy_endpoint_common_init (&pwr->e, &pwr->c, EK_PROXY_WRITER, guid, timestamp, seq, proxypp, as, plist);
+  if ((ret = proxy_endpoint_common_init (&pwr->e, &pwr->c, EK_PROXY_WRITER, guid, timestamp, seq, proxypp, as, plist)) != DDS_RETCODE_OK)
+  {
+    ddsrt_free (pwr);
+    return ret;
+  }
 
   ddsrt_avl_init (&pwr_readers_treedef, &pwr->readers);
   pwr->n_reliable_readers = 0;
@@ -4275,7 +4301,19 @@ int new_proxy_writer (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
     nn_etime_t texpire = add_duration_to_etime (now_et (), pwr->c.xqos->liveliness.lease_duration);
     pwr->lease = lease_new (texpire, pwr->c.xqos->liveliness.lease_duration, &pwr->e);
     if (pwr->c.xqos->liveliness.kind != DDS_LIVELINESS_MANUAL_BY_TOPIC)
-      proxy_participant_add_pwr_lease (proxypp, pwr);
+    {
+      ddsrt_mutex_lock (&proxypp->e.lock);
+      proxy_participant_add_pwr_lease_locked (proxypp, pwr);
+      ddsrt_mutex_unlock (&proxypp->e.lock);
+    }
+    else
+    {
+      lease_register (pwr->lease);
+    }
+  }
+  else
+  {
+    pwr->lease = NULL;
   }
 
   if (isreliable)
@@ -4419,17 +4457,22 @@ static void gc_delete_proxy_writer (struct gcreq *gcreq)
     free_pwr_rd_match (m);
   }
   local_reader_ary_fini (&pwr->rdary);
+  if (pwr->c.xqos->liveliness.lease_duration != T_NEVER)
+    lease_free (pwr->lease);
   proxy_endpoint_common_fini (&pwr->e, &pwr->c);
   nn_defrag_free (pwr->defrag);
   nn_reorder_free (pwr->reorder);
   ddsrt_free (pwr);
 }
 
-int delete_proxy_writer (struct q_globals *gv, const struct ddsi_guid *guid, nn_wctime_t timestamp, int isimplicit, bool proxypp_locked)
+/* First stage in deleting the proxy writer. In this function the pwr and its member pointers
+   will remain valid. The real cleaning-up is done async in gc_delete_proxy_writer. */
+int delete_proxy_writer (struct q_globals *gv, const struct ddsi_guid *guid, nn_wctime_t timestamp, int isimplicit)
 {
   struct proxy_writer *pwr;
-  (void)isimplicit;
+  DDSRT_UNUSED_ARG (isimplicit);
   GVLOGDISC ("delete_proxy_writer ("PGUIDFMT") ", PGUID (*guid));
+
   ddsrt_mutex_lock (&gv->lock);
   if ((pwr = ephash_lookup_proxy_writer_guid (gv->guid_hash, guid)) == NULL)
   {
@@ -4446,66 +4489,60 @@ int delete_proxy_writer (struct q_globals *gv, const struct ddsi_guid *guid, nn_
   builtintopic_write (gv->builtin_topic_interface, &pwr->e, timestamp, false);
   ephash_remove_proxy_writer_guid (gv->guid_hash, pwr);
   ddsrt_mutex_unlock (&gv->lock);
+  if (proxy_writer_set_notalive (pwr) != DDS_RETCODE_OK)
+    GVLOGDISC ("proxy_writer_set_notalive failed for "PGUIDFMT"\n", PGUID(*guid));
+  /* Set lease expiry for this pwr to never so that the pwr will not be set
+     to alive again while it is scheduled for being deleted. */
   if (pwr->c.xqos->liveliness.lease_duration != T_NEVER)
-  {
-    ddsrt_mutex_lock (&pwr->e.lock);
-    if (pwr->alive && pwr->c.xqos->liveliness.kind != DDS_LIVELINESS_MANUAL_BY_TOPIC)
-      proxypp_locked ? proxy_participant_remove_pwr_lease_locked (pwr->c.proxypp, pwr) : proxy_participant_remove_pwr_lease (pwr->c.proxypp, pwr);
-    ddsrt_mutex_unlock (&pwr->e.lock);
-    lease_free (pwr->lease);
-  }
+    lease_renew (pwr->lease, (nn_etime_t){ T_NEVER });
   gcreq_proxy_writer (pwr);
-  return 0;
+  return DDS_RETCODE_OK;
 }
 
-int proxy_writer_set_alive_locked (struct q_globals *gv, struct proxy_writer *pwr, bool alive)
+int proxy_writer_set_alive (struct proxy_writer *pwr)
 {
+  /* Caller has pwr->e.lock, so we can safely read pwr->alive. For updating
+   * this field this function is also taking pwr->c.proxypp->e.lock */
   ddsrt_avl_iter_t it;
-  assert (pwr->alive != alive);
-  pwr->alive = alive;
-  GVLOGDISC (" alive=%d", pwr->alive);
   if (pwr->alive)
+    return DDS_RETCODE_PRECONDITION_NOT_MET;
+  ddsrt_mutex_lock (&pwr->c.proxypp->e.lock);
+  pwr->alive = true;
+
+  for (struct pwr_rd_match *m = ddsrt_avl_iter_first (&pwr_readers_treedef, &pwr->readers, &it); m != NULL; m = ddsrt_avl_iter_next (&it))
   {
-    for (struct pwr_rd_match *m = ddsrt_avl_iter_first (&pwr_readers_treedef, &pwr->readers, &it); m != NULL; m = ddsrt_avl_iter_next (&it))
+    struct reader *rd;
+    if ((rd = ephash_lookup_reader_guid (pwr->e.gv->guid_hash, &m->rd_guid)) != NULL)
     {
-      struct reader *rd;
-      if ((rd = ephash_lookup_reader_guid (pwr->e.gv->guid_hash, &m->rd_guid)) != NULL)
-      {
-        status_cb_data_t data;
-        data.add = true;
-        data.handle = pwr->e.iid;
-        data.raw_status_id = (int) DDS_LIVELINESS_CHANGED_STATUS_ID;
-        (rd->status_cb) (rd->status_cb_entity, &data);
-      }
+      status_cb_data_t data;
+      data.add = true;
+      data.handle = pwr->e.iid;
+      data.raw_status_id = (int) DDS_LIVELINESS_CHANGED_STATUS_ID;
+      (rd->status_cb) (rd->status_cb_entity, &data);
     }
-    if (pwr->c.xqos->liveliness.lease_duration != T_NEVER && pwr->c.xqos->liveliness.kind != DDS_LIVELINESS_MANUAL_BY_TOPIC)
-      proxy_participant_add_pwr_lease (pwr->c.proxypp, pwr);
   }
+  if (pwr->c.xqos->liveliness.lease_duration != T_NEVER && pwr->c.xqos->liveliness.kind != DDS_LIVELINESS_MANUAL_BY_TOPIC)
+    proxy_participant_add_pwr_lease_locked (pwr->c.proxypp, pwr);
+  ddsrt_mutex_unlock (&pwr->c.proxypp->e.lock);
+  return DDS_RETCODE_OK;
+}
+
+int proxy_writer_set_notalive (struct proxy_writer *pwr)
+{
+  /* Caller should not have taken pwr->e.lock and pwr->c.proxypp->e.lock;
+   * this function takes both locks to update pwr->alive value */
+  int ret = DDS_RETCODE_OK;
+  ddsrt_mutex_lock (&pwr->e.lock);
+  if (!pwr->alive)
+    ret = DDS_RETCODE_PRECONDITION_NOT_MET;
   else
   {
-    for (struct pwr_rd_match *m = ddsrt_avl_iter_first (&pwr_readers_treedef, &pwr->readers, &it); m != NULL; m = ddsrt_avl_iter_next (&it))
-      reader_drop_connection (&m->rd_guid, pwr, false);
+    ddsrt_mutex_lock (&pwr->c.proxypp->e.lock);
+    pwr->alive = false;
     if (pwr->c.xqos->liveliness.lease_duration != T_NEVER && pwr->c.xqos->liveliness.kind != DDS_LIVELINESS_MANUAL_BY_TOPIC)
-      proxy_participant_remove_pwr_lease (pwr->c.proxypp, pwr);
+      proxy_participant_remove_pwr_lease_locked (pwr->c.proxypp, pwr);
+    ddsrt_mutex_unlock (&pwr->c.proxypp->e.lock);
   }
-  return 0;
-}
-
-int proxy_writer_set_alive_guid (struct q_globals *gv, const struct ddsi_guid *guid, bool alive)
-{
-  struct proxy_writer *pwr;
-  int ret;
-  ddsrt_mutex_lock (&gv->lock);
-  if ((pwr = ephash_lookup_proxy_writer_guid (gv->guid_hash, guid)) == NULL)
-  {
-    ddsrt_mutex_unlock (&gv->lock);
-    GVLOGDISC (" "PGUIDFMT"?\n", PGUID (*guid));
-    return DDS_RETCODE_BAD_PARAMETER;
-  }
-  ddsrt_mutex_unlock (&gv->lock);
-
-  ddsrt_mutex_lock (&pwr->e.lock);
-  ret = proxy_writer_set_alive_locked (gv, pwr, alive);
   ddsrt_mutex_unlock (&pwr->e.lock);
   return ret;
 }
@@ -4521,6 +4558,7 @@ int new_proxy_reader (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
   struct proxy_participant *proxypp;
   struct proxy_reader *prd;
   nn_mtime_t tnow = now_mt ();
+  int ret;
 
   assert (!is_writer_entityid (guid->entityid));
   assert (ephash_lookup_proxy_reader_guid (gv->guid_hash, guid) == NULL);
@@ -4532,7 +4570,11 @@ int new_proxy_reader (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
   }
 
   prd = ddsrt_malloc (sizeof (*prd));
-  proxy_endpoint_common_init (&prd->e, &prd->c, EK_PROXY_READER, guid, timestamp, seq, proxypp, as, plist);
+  if ((ret = proxy_endpoint_common_init (&prd->e, &prd->c, EK_PROXY_READER, guid, timestamp, seq, proxypp, as, plist)) != DDS_RETCODE_OK)
+  {
+    ddsrt_free (prd);
+    return ret;
+  }
 
   prd->deleting = 0;
 #ifdef DDSI_INCLUDE_SSM
@@ -4549,7 +4591,7 @@ int new_proxy_reader (struct q_globals *gv, const struct ddsi_guid *ppguid, cons
   ddsrt_mutex_unlock (&prd->e.lock);
 
   match_proxy_reader_with_writers (prd, tnow);
-  return 0;
+  return DDS_RETCODE_OK;
 }
 
 static void proxy_reader_set_delete_and_ack_all_messages (struct proxy_reader *prd)
diff --git a/src/core/ddsi/src/q_lease.c b/src/core/ddsi/src/q_lease.c
index f107855..0db530c 100644
--- a/src/core/ddsi/src/q_lease.c
+++ b/src/core/ddsi/src/q_lease.c
@@ -140,7 +140,6 @@ void lease_free (struct lease *l)
 
 void lease_renew (struct lease *l, nn_etime_t tnowE)
 {
-  struct q_globals const * gv;
   nn_etime_t tend_new = add_duration_to_etime (tnowE, l->tdur);
 
   /* do not touch tend if moving forward or if already expired */
@@ -151,7 +150,11 @@ void lease_renew (struct lease *l, nn_etime_t tnowE)
       return;
   } while (!ddsrt_atomic_cas64 (&l->tend, (uint64_t) tend, (uint64_t) tend_new.v));
 
-  gv = l->entity->gv;
+  /* Only at this point we can assume that gv can be recovered from the entity in the
+   * lease (i.e. the entity still exists). In cases where dereferencing l->entity->gv
+   * is not safe (e.g. the deletion of entities), the early out in the loop above
+   * will be the case because tend is set to T_NEVER. */
+  struct q_globals const * gv = l->entity->gv;
   if (gv->logconfig.c.mask & DDS_LC_TRACE)
   {
     int32_t tsec, tusec;
@@ -272,10 +275,27 @@ int64_t check_and_handle_lease_expiration (struct q_globals *gv, nn_etime_t tnow
         delete_proxy_participant_by_guid (gv, &g, now(), 1);
         break;
       case EK_PROXY_WRITER:
-        GVLOGDISC ("proxy_writer_set_alive ("PGUIDFMT")", PGUID (g));
-        (void) proxy_writer_set_alive_guid (gv, &g, false);
+      {
+        struct proxy_writer *pwr;
+        ddsrt_avl_iter_t it;
+        if ((pwr = ephash_lookup_proxy_writer_guid (gv->guid_hash, &g)) == NULL)
+        {
+          GVLOGDISC (" "PGUIDFMT"?\n", PGUID (g));
+          ddsrt_mutex_lock (&gv->leaseheap_lock);
+          continue;
+        }
+        GVLOGDISC ("proxy_writer_set_notalive ("PGUIDFMT")", PGUID (g));
+        if (proxy_writer_set_notalive (pwr) == DDS_RETCODE_PRECONDITION_NOT_MET)
+        {
+          GVLOGDISC (" pwr was not alive");
+          ddsrt_mutex_lock (&gv->leaseheap_lock);
+          continue;
+        }
         GVLOGDISC ("\n");
+        for (struct pwr_rd_match *m = ddsrt_avl_iter_first (&pwr_readers_treedef, &pwr->readers, &it); m != NULL; m = ddsrt_avl_iter_next (&it))
+          reader_drop_connection (&m->rd_guid, pwr, false);
         break;
+      }
       case EK_PARTICIPANT:
       case EK_READER:
       case EK_WRITER:
@@ -283,7 +303,6 @@ int64_t check_and_handle_lease_expiration (struct q_globals *gv, nn_etime_t tnow
         assert (false);
         break;
     }
-
     ddsrt_mutex_lock (&gv->leaseheap_lock);
   }
 
diff --git a/src/core/ddsi/src/q_receive.c b/src/core/ddsi/src/q_receive.c
index 4bea8e8..b026022 100644
--- a/src/core/ddsi/src/q_receive.c
+++ b/src/core/ddsi/src/q_receive.c
@@ -548,7 +548,7 @@ static void force_heartbeat_to_peer (struct writer *wr, const struct whc_state *
   }
 
   /* Send a Heartbeat just to this peer */
-  add_Heartbeat (m, wr, whcst, hbansreq, prd->e.guid.entityid, 0);
+  add_Heartbeat (m, wr, whcst, hbansreq, 0, prd->e.guid.entityid, 0);
   ETRACE (wr, "force_heartbeat_to_peer: "PGUIDFMT" -> "PGUIDFMT" - queue for transmit\n",
           PGUID (wr->e.guid), PGUID (prd->e.guid));
   qxev_msg (wr->evq, m);
@@ -1131,12 +1131,18 @@ static int handle_Heartbeat (struct receiver_state *rst, nn_etime_t tnow, struct
     RSTTRACE (PGUIDFMT"? -> "PGUIDFMT")", PGUID (src), PGUID (dst));
     return 1;
   }
-
   lease_renew (ddsrt_atomic_ldvoidp (&pwr->c.proxypp->minl_auto), tnow);
   RSTTRACE (PGUIDFMT" -> "PGUIDFMT":", PGUID (src), PGUID (dst));
-
   ddsrt_mutex_lock (&pwr->e.lock);
-
+  if (msg->smhdr.flags & HEARTBEAT_FLAG_LIVELINESS &&
+      pwr->c.xqos->liveliness.kind == DDS_LIVELINESS_MANUAL_BY_TOPIC &&
+      pwr->c.xqos->liveliness.lease_duration != T_NEVER)
+  {
+    struct lease *lease = ddsrt_atomic_ldvoidp (&pwr->c.proxypp->minl_man);
+    if (lease != NULL)
+      lease_renew (lease, tnow);
+    lease_renew (pwr->lease, tnow);
+  }
   if (pwr->n_reliable_readers == 0)
   {
     RSTTRACE (PGUIDFMT" -> "PGUIDFMT" no-reliable-readers)", PGUID (src), PGUID (dst));
@@ -2087,7 +2093,8 @@ static void clean_defrag (struct proxy_writer *pwr)
   nn_defrag_notegap (pwr->defrag, 1, seq);
 }
 
-static void handle_regular (struct receiver_state *rst, nn_etime_t tnow, struct nn_rmsg *rmsg, const Data_DataFrag_common_t *msg, const struct nn_rsample_info *sampleinfo, uint32_t fragnum, struct nn_rdata *rdata, struct nn_dqueue **deferred_wakeup, bool renew_manbypp_lease)
+static void handle_regular (struct receiver_state *rst, nn_etime_t tnow, struct nn_rmsg *rmsg, const Data_DataFrag_common_t *msg, const struct nn_rsample_info *sampleinfo,
+    uint32_t fragnum, struct nn_rdata *rdata, struct nn_dqueue **deferred_wakeup, bool renew_manbypp_lease)
 {
   struct proxy_writer *pwr;
   struct nn_rsample *rsample;
@@ -2114,13 +2121,11 @@ static void handle_regular (struct receiver_state *rst, nn_etime_t tnow, struct
   /* Shouldn't lock the full writer, but will do so for now */
   ddsrt_mutex_lock (&pwr->e.lock);
 
-  /* FIXME: implement liveliness manual-by-topic */
-  /* if (pwr->c.xqos->liveliness.kind == DDS_LIVELINESS_MANUAL_BY_TOPIC)
+  if (pwr->c.xqos->liveliness.kind == DDS_LIVELINESS_MANUAL_BY_TOPIC && pwr->c.xqos->liveliness.lease_duration != T_NEVER)
     lease_renew (pwr->lease, tnow);
-  */
 
   if (!pwr->alive)
-    proxy_writer_set_alive_locked (pwr->e.gv, pwr, true);
+    proxy_writer_set_alive (pwr);
 
   /* Don't accept data when reliable readers exist and we haven't yet seen
      a heartbeat telling us what the "current" sequence number of the writer
diff --git a/src/core/ddsi/src/q_transmit.c b/src/core/ddsi/src/q_transmit.c
index 7afd1fe..6d2a69a 100644
--- a/src/core/ddsi/src/q_transmit.c
+++ b/src/core/ddsi/src/q_transmit.c
@@ -194,7 +194,7 @@ struct nn_xmsg *writer_hbcontrol_create_heartbeat (struct writer *wr, const stru
 #ifdef DDSI_INCLUDE_NETWORK_PARTITIONS
     nn_xmsg_setencoderid (msg, wr->partition_id);
 #endif
-    add_Heartbeat (msg, wr, whcst, hbansreq, to_entityid (NN_ENTITYID_UNKNOWN), issync);
+    add_Heartbeat (msg, wr, whcst, hbansreq, 0, to_entityid (NN_ENTITYID_UNKNOWN), issync);
   }
   else
   {
@@ -215,7 +215,7 @@ struct nn_xmsg *writer_hbcontrol_create_heartbeat (struct writer *wr, const stru
 #ifdef DDSI_INCLUDE_NETWORK_PARTITIONS
     nn_xmsg_setencoderid (msg, wr->partition_id);
 #endif
-    add_Heartbeat (msg, wr, whcst, hbansreq, prd_guid->entityid, issync);
+    add_Heartbeat (msg, wr, whcst, hbansreq, 0, prd_guid->entityid, issync);
   }
 
   writer_hbcontrol_note_hb (wr, tnow, hbansreq);
@@ -313,7 +313,7 @@ struct nn_xmsg *writer_hbcontrol_piggyback (struct writer *wr, const struct whc_
   return msg;
 }
 
-void add_Heartbeat (struct nn_xmsg *msg, struct writer *wr, const struct whc_state *whcst, int hbansreq, ddsi_entityid_t dst, int issync)
+void add_Heartbeat (struct nn_xmsg *msg, struct writer *wr, const struct whc_state *whcst, int hbansreq, int hbliveliness, ddsi_entityid_t dst, int issync)
 {
   struct q_globals const * const gv = wr->e.gv;
   struct nn_xmsg_marker sm_marker;
@@ -324,6 +324,7 @@ void add_Heartbeat (struct nn_xmsg *msg, struct writer *wr, const struct whc_sta
 
   assert (wr->reliable);
   assert (hbansreq >= 0);
+  assert (hbliveliness >= 0);
 
   if (gv->config.meas_hb_to_ack_latency)
   {
@@ -337,6 +338,8 @@ void add_Heartbeat (struct nn_xmsg *msg, struct writer *wr, const struct whc_sta
 
   if (!hbansreq)
     hb->smhdr.flags |= HEARTBEAT_FLAG_FINAL;
+  if (hbliveliness)
+    hb->smhdr.flags |= HEARTBEAT_FLAG_LIVELINESS;
 
   hb->readerId = nn_hton_entityid (dst);
   hb->writerId = nn_hton_entityid (wr->e.guid.entityid);
@@ -666,6 +669,34 @@ static void create_HeartbeatFrag (struct writer *wr, seqno_t seq, unsigned fragn
   nn_xmsg_submsg_setnext (*pmsg, sm_marker);
 }
 
+dds_return_t write_hb_liveliness (struct q_globals * const gv, struct ddsi_guid *wr_guid, struct nn_xpack *xp)
+{
+  struct nn_xmsg *msg = NULL;
+  struct whc_state whcst;
+  struct thread_state1 * const ts1 = lookup_thread_state ();
+  thread_state_awake (ts1, gv);
+  struct writer *wr = ephash_lookup_writer_guid (gv->guid_hash, wr_guid);
+  if (wr == NULL)
+  {
+    GVTRACE ("write_hb_liveliness("PGUIDFMT") - writer not found\n", PGUID (*wr_guid));
+    return DDS_RETCODE_PRECONDITION_NOT_MET;
+  }
+  if ((msg = nn_xmsg_new (gv->xmsgpool, &wr->e.guid.prefix, sizeof (InfoTS_t) + sizeof (Heartbeat_t), NN_XMSG_KIND_CONTROL)) == NULL)
+    return DDS_RETCODE_OUT_OF_RESOURCES;
+  ddsrt_mutex_lock (&wr->e.lock);
+  nn_xmsg_setdstN (msg, wr->as, wr->as_group);
+#ifdef DDSI_INCLUDE_NETWORK_PARTITIONS
+  nn_xmsg_setencoderid (msg, wr->partition_id);
+#endif
+  whc_get_state (wr->whc, &whcst);
+  add_Heartbeat (msg, wr, &whcst, 0, 1, to_entityid (NN_ENTITYID_UNKNOWN), 1);
+  ddsrt_mutex_unlock (&wr->e.lock);
+  nn_xpack_addmsg (xp, msg, 0);
+  nn_xpack_send (xp, true);
+  thread_state_asleep (ts1);
+  return DDS_RETCODE_OK;
+}
+
 #if 0
 static int must_skip_frag (const char *frags_to_skip, unsigned frag)
 {