diff --git a/doc/PLUGINS.md b/doc/PLUGINS.md
index cfb9a6c03..644f3a254 100644
--- a/doc/PLUGINS.md
+++ b/doc/PLUGINS.md
@@ -1212,7 +1212,7 @@ The payload for a call follows this format:
 ```json
 {
 	"peer_id": "02df5ffe895c778e10f7742a6c5b8a0cefbe9465df58b92fadeb883752c8107c8f",
-	"message": "1337ffffffff"
+	"payload": "1337ffffffff"
 }
 ```
 
diff --git a/lightningd/peer_control.c b/lightningd/peer_control.c
index 7f87bf549..086b21821 100644
--- a/lightningd/peer_control.c
+++ b/lightningd/peer_control.c
@@ -2454,7 +2454,16 @@ static void custommsg_final(struct custommsg_payload *payload STEALS)
 static void custommsg_payload_serialize(struct custommsg_payload *payload,
 					struct json_stream *stream)
 {
-	json_add_hex_talarr(stream, "message", payload->msg);
+	if (deprecated_apis) {
+		json_add_hex_talarr(stream, "message", payload->msg);
+		json_add_string(
+		    stream, "warning",
+		    "The `message` field is deprecated and has been replaced "
+		    "with the payload` field which skips the internal type and "
+		    "the length prefix. Please update to use that instead.");
+	}
+	json_add_hex(stream, "payload", payload->msg + 4,
+		     tal_bytelen(payload->msg) - 4);
 	json_add_node_id(stream, "peer_id", &payload->peer_id);
 }
 
diff --git a/tests/plugins/custommsg_a.py b/tests/plugins/custommsg_a.py
index fcc7ac133..731adb144 100755
--- a/tests/plugins/custommsg_a.py
+++ b/tests/plugins/custommsg_a.py
@@ -5,9 +5,9 @@ plugin = Plugin()
 
 
 @plugin.hook('custommsg')
-def on_custommsg(peer_id, message, plugin, **kwargs):
+def on_custommsg(peer_id, payload, plugin, message=None, **kwargs):
     plugin.log("Got custommessage_a {msg} from peer {peer_id}".format(
-        msg=message,
+        msg=payload,
         peer_id=peer_id
     ))
     return {'result': 'continue'}
diff --git a/tests/plugins/custommsg_b.py b/tests/plugins/custommsg_b.py
index 3f9ab307b..6282701f4 100755
--- a/tests/plugins/custommsg_b.py
+++ b/tests/plugins/custommsg_b.py
@@ -5,9 +5,9 @@ plugin = Plugin()
 
 
 @plugin.hook('custommsg')
-def on_custommsg(peer_id, message, plugin, **kwargs):
+def on_custommsg(peer_id, payload, plugin, message=None, **kwargs):
     plugin.log("Got custommessage_b {msg} from peer {peer_id}".format(
-        msg=message,
+        msg=payload,
         peer_id=peer_id
     ))
     return {'result': 'continue'}
diff --git a/tests/test_misc.py b/tests/test_misc.py
index ee2d6415f..11a472c80 100644
--- a/tests/test_misc.py
+++ b/tests/test_misc.py
@@ -2284,10 +2284,10 @@ def test_sendcustommsg(node_factory):
     )
     l1.daemon.wait_for_log(r'\[IN\] {}'.format(serialized))
     l1.daemon.wait_for_logs([
-        r'Got custommessage_a {serialized} from peer {peer_id}'.format(
-            serialized=serialized, peer_id=l2.info['id']),
-        r'Got custommessage_b {serialized} from peer {peer_id}'.format(
-            serialized=serialized, peer_id=l2.info['id'])
+        r'Got custommessage_a {msg} from peer {peer_id}'.format(
+            msg=msg, peer_id=l2.info['id']),
+        r'Got custommessage_b {msg} from peer {peer_id}'.format(
+            msg=msg, peer_id=l2.info['id'])
     ])
 
     # This should work since the peer is currently owned by `openingd`
@@ -2299,10 +2299,10 @@ def test_sendcustommsg(node_factory):
     )
     l4.daemon.wait_for_log(r'\[IN\] {}'.format(serialized))
     l4.daemon.wait_for_logs([
-        r'Got custommessage_a {serialized} from peer {peer_id}'.format(
-            serialized=serialized, peer_id=l2.info['id']),
-        r'Got custommessage_b {serialized} from peer {peer_id}'.format(
-            serialized=serialized, peer_id=l2.info['id']),
+        r'Got custommessage_a {msg} from peer {peer_id}'.format(
+            msg=msg, peer_id=l2.info['id']),
+        r'Got custommessage_b {msg} from peer {peer_id}'.format(
+            msg=msg, peer_id=l2.info['id']),
     ])
 
 
diff --git a/wallet/db_postgres_sqlgen.c b/wallet/db_postgres_sqlgen.c
index a805cdcb7..7707b9dd4 100644
--- a/wallet/db_postgres_sqlgen.c
+++ b/wallet/db_postgres_sqlgen.c
@@ -1792,4 +1792,4 @@ struct db_query db_postgres_queries[] = {
 
 #endif /* LIGHTNINGD_WALLET_GEN_DB_POSTGRES */
 
-// SHA256STAMP:d5554774287ded802c96fc975565e5557e5f7e174fea04ad7ec080400a15992b
+// SHA256STAMP:759b19435d68328d597f6540e1f4f8c42ce22ef91dbf66c1098de0434462546c
diff --git a/wallet/db_sqlite3_sqlgen.c b/wallet/db_sqlite3_sqlgen.c
index 600791b57..4212510f4 100644
--- a/wallet/db_sqlite3_sqlgen.c
+++ b/wallet/db_sqlite3_sqlgen.c
@@ -1792,4 +1792,4 @@ struct db_query db_sqlite3_queries[] = {
 
 #endif /* LIGHTNINGD_WALLET_GEN_DB_SQLITE3 */
 
-// SHA256STAMP:d5554774287ded802c96fc975565e5557e5f7e174fea04ad7ec080400a15992b
+// SHA256STAMP:759b19435d68328d597f6540e1f4f8c42ce22ef91dbf66c1098de0434462546c
diff --git a/wallet/statements_gettextgen.po b/wallet/statements_gettextgen.po
index fbed496ec..5a7b1ac35 100644
--- a/wallet/statements_gettextgen.po
+++ b/wallet/statements_gettextgen.po
@@ -1178,7 +1178,7 @@ msgstr ""
 msgid "not a valid SQL statement"
 msgstr ""
 
-#: wallet/test/run-wallet.c:1395
+#: wallet/test/run-wallet.c:1399
 msgid "INSERT INTO channels (id) VALUES (1);"
 msgstr ""
-#  SHA256STAMP:6aef0052df3b7141edbb7af83a1242a31af18b55aed8e14ca5ede7d783f86309
+#  SHA256STAMP:c51857ae4385dd151d6a60f5ce99a5227a9a0cd01a66e0507bb81c04db07c39e
diff --git a/wallet/test/run-wallet.c b/wallet/test/run-wallet.c
index 04d23ebf9..6a1520573 100644
--- a/wallet/test/run-wallet.c
+++ b/wallet/test/run-wallet.c
@@ -272,6 +272,10 @@ void json_add_amount_sat_compat(struct json_stream *result UNNEEDED,
 void json_add_bool(struct json_stream *result UNNEEDED, const char *fieldname UNNEEDED,
 		   bool value UNNEEDED)
 { fprintf(stderr, "json_add_bool called!\n"); abort(); }
+/* Generated stub for json_add_hex */
+void json_add_hex(struct json_stream *result UNNEEDED, const char *fieldname UNNEEDED,
+		  const void *data UNNEEDED, size_t len UNNEEDED)
+{ fprintf(stderr, "json_add_hex called!\n"); abort(); }
 /* Generated stub for json_add_hex_talarr */
 void json_add_hex_talarr(struct json_stream *result UNNEEDED,
 			 const char *fieldname UNNEEDED,