diff --git a/lib/AmsData/src/AmsData.cpp b/lib/AmsData/src/AmsData.cpp
index bc2a2491..66e5fea5 100644
--- a/lib/AmsData/src/AmsData.cpp
+++ b/lib/AmsData/src/AmsData.cpp
@@ -82,7 +82,7 @@ void AmsData::apply(AmsData& other) {
         this->activeExportPower = other.getActiveExportPower();
 }
 
-unsigned long AmsData::getLastUpdateMillis() {
+uint64_t AmsData::getLastUpdateMillis() {
     return this->lastUpdateMillis;
 }