Handle missing subentry support

custom_components/ha_knx_bridge/config_flow.py

@@ -69,7 +69,10 @@ class HAKnxBridgeConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
     @callback
     def async_get_supported_subentry_types(config_entry):
         if _SUBENTRY_TYPE is None:
-            raise NotImplementedError("Subentry types are not supported in this HA version")
+            _LOGGER.warning(
+                "Config subentries are not supported in this Home Assistant version"
+            )
+            return {}
         return {
             "binary_sensor": _SUBENTRY_TYPE(
                 name="Binary Sensor Port", flow_class=BinarySensorPortSubentryFlow