diff --git a/platformio.ini-example b/platformio.ini-example
index 0f68ed9f8..4a15036c4 100644
--- a/platformio.ini-example
+++ b/platformio.ini-example
@@ -4,7 +4,7 @@ env_default = nodemcuv2
 
 [common]
 platform = espressif8266
-; optional flags are -DUSE_LED -DSHOWER_TEST -DDEBUG
+; optional flags are -DUSE_LED -DSHOWER_TEST -DDEBUG -DUSE_SERIAL
 build_flags = -DMQTT_MAX_PACKET_SIZE=300
 build_flags_custom = '-DWIFI_SSID="my_ssid"' '-DWIFI_PASSWORD="my_password"' '-DMQTT_IP="my_broker_ip"' '-DMQTT_USER="my_broker_username"' '-DMQTT_PASS="my_broker_password"' 
 lib_deps =