diff --git a/src/main/java/de/csdev/ebus/command/datatypes/ext/EBusTypeDateTime.java b/src/main/java/de/csdev/ebus/command/datatypes/ext/EBusTypeDateTime.java
index 6bfebec..3cb9fff 100644
--- a/src/main/java/de/csdev/ebus/command/datatypes/ext/EBusTypeDateTime.java
+++ b/src/main/java/de/csdev/ebus/command/datatypes/ext/EBusTypeDateTime.java
@@ -52,7 +52,7 @@ public class EBusTypeDateTime extends EBusAbstractType<EBusDateTime> {
     private String variantTime = EBusTypeTime.DEFAULT;
 
     @Override
-    protected byte[] applyByteOrder(byte[] data) {
+    protected byte @Nullable [] applyByteOrder(byte @Nullable [] data) {
         if (reverseByteOrder) {
             logger.warn("Parameter 'reverseByteOrder' not supported for EBusTypeDateTime yet!");
         }