diff --git a/include/libwebsockets/lws-client.h b/include/libwebsockets/lws-client.h
index 9108484de..76c80069c 100644
--- a/include/libwebsockets/lws-client.h
+++ b/include/libwebsockets/lws-client.h
@@ -247,6 +247,18 @@ struct lws_client_connect_info {
 	const char *auth_username;
 	const char *auth_password;
 
+#if defined(LWS_ROLE_WS)
+	uint8_t		allow_reserved_bits;
+	/**< non-zero to allow reserved bits. You can get it by lws_get_reserved_bits().
+	 * Note: default zero means close the websocket connection for non-zero rsv.
+	 */
+
+	uint8_t		allow_unknown_opcode;
+	/**< non-zero to allow unknown opcode. You can get it by `lws_get_opcode`.
+	 * None: default zero means close the websocket connection for unknown opcode.
+	 */
+#endif
+
 	/* Add new things just above here ---^
 	 * This is part of the ABI, don't needlessly break compatibility
 	 *
diff --git a/include/libwebsockets/lws-ws-state.h b/include/libwebsockets/lws-ws-state.h
index d21c2a75b..b1cc54633 100644
--- a/include/libwebsockets/lws-ws-state.h
+++ b/include/libwebsockets/lws-ws-state.h
@@ -60,6 +60,13 @@ lws_is_first_fragment(struct lws *wsi);
 LWS_VISIBLE LWS_EXTERN unsigned char
 lws_get_reserved_bits(struct lws *wsi);
 
+/**
+ * lws_get_opcode() - access opcode of ws frame
+ * \param wsi: lws connection
+ */
+LWS_VISIBLE LWS_EXTERN uint8_t
+lws_get_opcode(struct lws *wsi);
+
 /**
  * lws_partial_buffered() - find out if lws buffered the last write
  * \param wsi:	websocket connection to check
diff --git a/lib/roles/ws/client-parser-ws.c b/lib/roles/ws/client-parser-ws.c
index f67927b2a..34dc69741 100644
--- a/lib/roles/ws/client-parser-ws.c
+++ b/lib/roles/ws/client-parser-ws.c
@@ -119,6 +119,8 @@ int lws_ws_client_rx_sm(struct lws *wsi, unsigned char c)
 			case 0xd:
 			case 0xe:
 			case 0xf:
+				if (wsi->ws->allow_unknown_opcode)
+					break;
 				lwsl_wsi_info(wsi, "illegal opcode");
 				return -1;
 			default:
@@ -131,7 +133,7 @@ int lws_ws_client_rx_sm(struct lws *wsi, unsigned char c)
 #if !defined(LWS_WITHOUT_EXTENSIONS)
 				!wsi->ws->count_act_ext &&
 #endif
-				wsi->ws->rsv) {
+				wsi->ws->rsv && !wsi->ws->allow_reserved_bits) {
 				lwsl_wsi_info(wsi, "illegal rsv bits set");
 				return -1;
 			}
diff --git a/lib/roles/ws/client-ws.c b/lib/roles/ws/client-ws.c
index 750aea96f..ddae6edbf 100644
--- a/lib/roles/ws/client-ws.c
+++ b/lib/roles/ws/client-ws.c
@@ -62,6 +62,12 @@ lws_create_client_ws_object(const struct lws_client_connect_info *i,
 
 	wsi->ws->ietf_spec_revision = (uint8_t)v;
 
+	if (i->allow_reserved_bits)
+		wsi->ws->allow_reserved_bits = 1;
+
+	if (i->allow_unknown_opcode)
+		wsi->ws->allow_unknown_opcode = 1;
+
 	return 0;
 }
 
diff --git a/lib/roles/ws/ops-ws.c b/lib/roles/ws/ops-ws.c
index 3282d3dfe..85eb8de3a 100644
--- a/lib/roles/ws/ops-ws.c
+++ b/lib/roles/ws/ops-ws.c
@@ -893,6 +893,12 @@ lws_get_reserved_bits(struct lws *wsi)
 	return wsi->ws->rsv;
 }
 
+uint8_t
+lws_get_opcode(struct lws *wsi)
+{
+	return wsi->ws->opcode;
+}
+
 int
 lws_get_close_length(struct lws *wsi)
 {
diff --git a/lib/roles/ws/private-lib-roles-ws.h b/lib/roles/ws/private-lib-roles-ws.h
index 511547d1b..3814bf29d 100644
--- a/lib/roles/ws/private-lib-roles-ws.h
+++ b/lib/roles/ws/private-lib-roles-ws.h
@@ -148,6 +148,8 @@ struct _lws_websocket_related {
 	uint8_t stashed_write_type;
 	uint8_t tx_draining_stashed_wp;
 	uint8_t ietf_spec_revision;
+	uint8_t allow_reserved_bits;
+	uint8_t allow_unknown_opcode;
 #if !defined(LWS_WITHOUT_EXTENSIONS)
 	uint8_t count_act_ext;
 #endif