diff --git a/include/classes/IoTItem.h b/include/classes/IoTItem.h
index 794dae73..ff899a20 100644
--- a/include/classes/IoTItem.h
+++ b/include/classes/IoTItem.h
@@ -48,7 +48,7 @@ class IoTItem {
 
     virtual IoTGpio* getGpioDriver();
     virtual IoTItem* getRtcDriver();
-    virtual ulong getRtcUnixTime();
+    virtual unsigned long getRtcUnixTime();
 
     virtual void setValue(const IoTValue& Value, bool genEvent = true);
     virtual void setValue(const String& valStr, bool genEvent = true);
diff --git a/src/classes/IoTItem.cpp b/src/classes/IoTItem.cpp
index 3a5c9a7d..bb79c6b5 100644
--- a/src/classes/IoTItem.cpp
+++ b/src/classes/IoTItem.cpp
@@ -216,7 +216,7 @@ IoTItem* IoTItem::getRtcDriver() {
     return nullptr;
 }
 
-ulong IoTItem::getRtcUnixTime() {
+unsigned long IoTItem::getRtcUnixTime() {
     return 0;
 }