Optional features can be controlled via platformio.ini and are mentioned in firmware name on MQTT

esp32/include/ControllerConfiguration.h

@@ -80,14 +80,24 @@
 /** \addtogroup Configuration
  *  @{
  */
-#define FIRMWARE_VERSION "2.71 HW0.10b"
 
-#define TIMED_LIGHT_PIN CUSTOM1_PIN5
-#define FLOWMETER_PIN CUSTOM1_PIN1
 #ifdef FLOWMETER_PIN
     #define FLOWMETER_PULSES_PER_ML 2.2
+    #define FIRMWARE_FEATURE1   "Flow"
+#else
+    #define FIRMWARE_FEATURE1   ""
 #endif
 
+#ifdef TIMED_LIGHT_PIN
+    #define FIRMWARE_FEATURE2   "Light"
+#else
+    #define FIRMWARE_FEATURE2   ""
+#endif
+
+#define FIRMWARE_BASENAME "PlantControl"
+#define FIRMWARE_NAME FIRMWARE_BASENAME FIRMWARE_FEATURE1 FIRMWARE_FEATURE2
+#define FIRMWARE_VERSION "2.71 HW0.10b" 
+
 #define MOIST_SENSOR_MAX_FRQ               5200 // 60kHz (500Hz margin)
 #define MOIST_SENSOR_MIN_FRQ                500 // 0.5kHz (500Hz margin)
 

esp32/platformio.ini

@@ -20,6 +20,9 @@ build_flags = -DPIO_FRAMEWORK_ARDUINO_LWIP2_LOW_MEMORY
     -DPLANT4_SENSORTYPE=FREQUENCY_MOD_RESISTANCE_PROBE
     -DPLANT5_SENSORTYPE=FREQUENCY_MOD_RESISTANCE_PROBE
     -DPLANT6_SENSORTYPE=FREQUENCY_MOD_RESISTANCE_PROBE
+    -DTIMED_LIGHT_PIN=CUSTOM1_PIN5
+    -DFLOWMETER_PIN=CUSTOM1_PIN1
+
 board_build.partitions = defaultWithSmallerSpiffs.csv
 
 ;#https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/partition-tables.html

esp32/src/main.cpp

@@ -808,7 +808,7 @@ void safeSetup()
   }
 
   /************************* Start Homie Framework ***************/
-  Homie_setFirmware("PlantControl", FIRMWARE_VERSION);
+  Homie_setFirmware(FIRMWARE_NAME, FIRMWARE_VERSION);
   Homie.disableLedFeedback();
   Homie_setBrand("PlantControl");
   // Set default values