diff --git a/inc/serial_uart_mux.hpp b/inc/serial_uart_mux.hpp
index 1e954da..57b4c58 100644
--- a/inc/serial_uart_mux.hpp
+++ b/inc/serial_uart_mux.hpp
@@ -70,7 +70,7 @@
     void configSerialConsoleMux(size_t position);
     bool isOCPDebugCardPresent();
 
-    void handleEvent(sd_event_source*, int, uint32_t) {}
+    void handleEvent(sd_event_source*, int, uint32_t) override {}
 
   protected:
     size_t gpioLineCount;