diff --git a/include/osmocom/pcu/pcuif_proto.h b/include/osmocom/pcu/pcuif_proto.h
index 693a1d5..1dda160 100644
--- a/include/osmocom/pcu/pcuif_proto.h
+++ b/include/osmocom/pcu/pcuif_proto.h
@@ -3,10 +3,12 @@
 
 #include <osmocom/gsm/l1sap.h>
 #include <arpa/inet.h>
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/protocol/gsm_23_003.h>
 
 #define PCU_SOCK_DEFAULT	"/tmp/pcu_bts"
 
-#define PCU_IF_VERSION		0x0a
+#define PCU_IF_VERSION		0x0b
 #define TXT_MAX_LEN	128
 
 /* msg_type */
@@ -269,6 +271,17 @@
 	} cgi_ps;
 } __attribute__ ((packed));
 
+/* Struct to send a (confirmed) IMMEDIATE ASSIGNMENT message via PCH. The struct is sent as a data request
+ * (data_req) under SAPI PCU_IF_SAPI_PCH_DT. */
+struct gsm_pcu_if_pch_dt {
+	/* TLLI as reference for confirmation */
+	uint32_t tlli;
+	/* IMSI (to derive paging group) */
+	char imsi[OSMO_IMSI_BUF_SIZE];
+	/* GSM mac-block (with immediate assignment message) */
+	uint8_t data[GSM_MACBLOCK_LEN];
+} __attribute__((packed));
+
 struct gsm_pcu_if {
 	/* context based information */
 	uint8_t		msg_type;	/* message type */
diff --git a/src/bts.cpp b/src/bts.cpp
index 33ad4a6..504ba27 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -1103,7 +1103,6 @@
 
 void bts_snd_dl_ass(struct gprs_rlcmac_bts *bts, const struct gprs_rlcmac_dl_tbf *tbf)
 {
-	uint16_t pgroup = ms_paging_group(tbf_ms(tbf));
 	int plen;
 	const struct gprs_rlcmac_pdch *pdch;
 
@@ -1129,7 +1128,10 @@
 						    GSM_L1_BURST_TYPE_ACCESS_0);
 	if (plen >= 0) {
 		bts_do_rate_ctr_inc(bts, CTR_IMMEDIATE_ASSIGN_DL_TBF);
-		pcu_l1if_tx_pch(bts, immediate_assignment, plen, pgroup);
+		if (the_pcu->pcu_if_version >= 0x0b)
+			pcu_l1if_tx_pch_dt(bts, immediate_assignment, plen, tbf->imsi(), tbf->tlli());
+		else
+			pcu_l1if_tx_pch(bts, immediate_assignment, plen, ms_paging_group(tbf_ms(tbf)));
 	}
 
 	bitvec_free(immediate_assignment);
diff --git a/src/gprs_pcu.h b/src/gprs_pcu.h
index a9e40ea..ca52c30 100644
--- a/src/gprs_pcu.h
+++ b/src/gprs_pcu.h
@@ -134,6 +134,8 @@
 	struct si_cache *si_cache; /* ARFC+BSIC -> CGI PS cache */
 
 	struct osmo_timer_list update_stats_timer; /* Used to update some time_cc stats periodically */
+
+	uint8_t pcu_if_version;
 };
 
 
diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp
index 6c4ed22..14cc778 100644
--- a/src/pcu_l1_if.cpp
+++ b/src/pcu_l1_if.cpp
@@ -294,6 +294,24 @@
 	pcu_tx_data_req(bts, 0, 0, PCU_IF_SAPI_PCH, 0, 0, 0, data, sizeof(data));
 }
 
+/* Send a block via the paging channel and require a confirmation by the receiving end */
+void pcu_l1if_tx_pch_dt(struct gprs_rlcmac_bts *bts, bitvec *block, int plen, const char *imsi, uint32_t tlli)
+{
+	/* NOTE: This is in practice only used to transmit IMMEDIATE ASSIGNMENT messages through the paging channel and
+	 * it is not guaranteed to work with other message types. The prepended TLLI will be used as an identifier in
+	 * the confirmation message. */
+
+	struct gsm_pcu_if_pch_dt pch_dt;
+
+	pch_dt.tlli = tlli;
+	strcpy(pch_dt.imsi, imsi);
+
+	pch_dt.data[0] = (plen << 2) | 0x01;
+	bitvec_pack(block, pch_dt.data + 1);
+
+	pcu_tx_data_req(bts, 0, 0, PCU_IF_SAPI_PCH_DT, 0, 0, 0, (uint8_t*)&pch_dt, sizeof(pch_dt));
+}
+
 int pcu_tx_neigh_addr_res_req(struct gprs_rlcmac_bts *bts, const struct neigh_cache_entry_key *neigh_key)
 {
 	struct msgb *msg;
@@ -734,14 +752,22 @@
 	if (llist_count(&the_pcu->bts_list) > 1)
 		LOGP(DL1IF, LOGL_ERROR, "more than one BTS regsitered at this PCU. This PCU has only been tested with one BTS! OS#5930\n");
 
-	if (info_ind->version != PCU_IF_VERSION) {
-		fprintf(stderr, "PCU interface version number of BTS (%u) is "
-			"different (%u).\nPlease re-compile!\n",
+	LOGP(DL1IF, LOGL_DEBUG, "Info indication received:\n");
+
+	/* NOTE: The classic way to confirm an IMMEDIATE assignment is to send the whole MAC block payload back to the
+	 * PCU. So it is the MAC block itsself that serves a reference for the confirmation. This method has certain
+	 * disadvantages so it was replaced with a method that uses the TLLI as a reference ("Direct TLLI"). This new
+	 * method will replace the old one. The code that handles the old method will be removed in the foreseeable
+	 * future. (see also OS#5927) */
+	if (info_ind->version == 0x0a) {
+		LOGP(DL1IF, LOGL_NOTICE, "PCUIF version 10 is deprecated. OS#5927\n");
+	} else if (info_ind->version != PCU_IF_VERSION) {
+		fprintf(stderr, "PCU interface version number of BTS/BSC (%u) is different (%u).\nPlease use a BTS/BSC with a compatble interface!\n",
 			info_ind->version, PCU_IF_VERSION);
 		exit(-1);
 	}
 
-	LOGP(DL1IF, LOGL_DEBUG, "Info indication received:\n");
+	the_pcu->pcu_if_version = info_ind->version;
 
 	if (!(info_ind->flags & PCU_IF_FLAG_ACTIVE)) {
 		LOGP(DL1IF, LOGL_NOTICE, "BTS not available\n");
diff --git a/src/pcu_l1_if.h b/src/pcu_l1_if.h
index e7080d5..1827d84 100644
--- a/src/pcu_l1_if.h
+++ b/src/pcu_l1_if.h
@@ -149,6 +149,7 @@
 void pcu_l1if_tx_agch(struct gprs_rlcmac_bts *bts, bitvec *block, int len);
 
 void pcu_l1if_tx_pch(struct gprs_rlcmac_bts *bts, bitvec *block, int plen, uint16_t pgroup);
+void pcu_l1if_tx_pch_dt(struct gprs_rlcmac_bts *bts, bitvec *block, int plen, const char *imsi, uint32_t tlli);
 #endif
 
 #ifdef __cplusplus