diff --git a/tests/gsup/gsup_test.c b/tests/gsup/gsup_test.c
index 0936893..b3a8c77 100644
--- a/tests/gsup/gsup_test.c
+++ b/tests/gsup/gsup_test.c
@@ -280,6 +280,15 @@
 			0xde, 0xad, 0xbe, 0xef,
 	};
 
+	static const uint8_t send_ready_for_sm_ind[] = {
+		0x2c, /* OSMO_GSUP_MSGT_READY_FOR_SM_REQUEST */
+		TEST_IMSI_IE,
+
+		/* SM related IEs */
+		0x46, 0x01, /* Alert reason */
+			0x02, /* Memory Available (SMMA) */
+	};
+
 	static const struct test {
 		char *name;
 		const uint8_t *data;
@@ -327,6 +336,8 @@
 			send_mo_mt_forward_sm_rsp, sizeof(send_mo_mt_forward_sm_rsp)},
 		{"MO-/MT-ForwardSM Error",
 			send_mo_mt_forward_sm_err, sizeof(send_mo_mt_forward_sm_err)},
+		{"ReadyForSM (MSC -> SMSC) Indication",
+			send_ready_for_sm_ind, sizeof(send_ready_for_sm_ind)},
 	};
 
 	printf("Test GSUP message decoding/encoding\n");
@@ -394,7 +405,7 @@
 				 * FIXME: share the maximal IE value somehow
 				 * in order to avoid manual updating of this
 				 */
-				OSMO_ASSERT(t->data[j+0] <= OSMO_GSUP_SM_RP_MMS_IE);
+				OSMO_ASSERT(t->data[j+0] <= OSMO_GSUP_SM_ALERT_RSN_IE);
 				OSMO_ASSERT(t->data[j+1] <= ie_end - j - 2);
 
 				ie_end = j;
diff --git a/tests/gsup/gsup_test.err b/tests/gsup/gsup_test.err
index 4a1357c..236c38a 100644
--- a/tests/gsup/gsup_test.err
+++ b/tests/gsup/gsup_test.err
@@ -61,6 +61,9 @@
   generated message: 25 01 08 21 43 65 87 09 21 43 f5 30 04 de ad be ef 31 01 03 40 01 fa 44 01 af 
   original message:  25 01 08 21 43 65 87 09 21 43 f5 30 04 de ad be ef 31 01 03 40 01 fa 44 01 af 
   IMSI:              123456789012345
+  generated message: 2c 01 08 21 43 65 87 09 21 43 f5 46 01 02 
+  original message:  2c 01 08 21 43 65 87 09 21 43 f5 46 01 02 
+  IMSI:              123456789012345
   message 0: tested 11 truncations, 11 parse failures
   message 1: tested 14 truncations, 13 parse failures
   message 2: tested 83 truncations, 81 parse failures
@@ -82,6 +85,7 @@
   message 18: tested 44 truncations, 39 parse failures
   message 19: tested 20 truncations, 18 parse failures
   message 20: tested 26 truncations, 22 parse failures
+  message 21: tested 14 truncations, 13 parse failures
 DLGSUP Stopping DLGSUP logging
   message 0: tested 2816 modifications, 510 parse failures
   message 1: tested 3584 modifications, 770 parse failures
@@ -104,3 +108,4 @@
   message 18: tested 11264 modifications, 2307 parse failures
   message 19: tested 5120 modifications, 1031 parse failures
   message 20: tested 6656 modifications, 1546 parse failures
+  message 21: tested 3584 modifications, 771 parse failures
diff --git a/tests/gsup/gsup_test.ok b/tests/gsup/gsup_test.ok
index 7a9455d..36e35c8 100644
--- a/tests/gsup/gsup_test.ok
+++ b/tests/gsup/gsup_test.ok
@@ -41,4 +41,6 @@
           MO-/MT-ForwardSM Response OK
   Testing MO-/MT-ForwardSM Error
           MO-/MT-ForwardSM Error OK
+  Testing ReadyForSM (MSC -> SMSC) Indication
+          ReadyForSM (MSC -> SMSC) Indication OK
 Done.