diff --git a/src/main/java/org/asamk/signal/json/JsonMessageEnvelope.java b/src/main/java/org/asamk/signal/json/JsonMessageEnvelope.java
index 256b9751..4944a74d 100644
--- a/src/main/java/org/asamk/signal/json/JsonMessageEnvelope.java
+++ b/src/main/java/org/asamk/signal/json/JsonMessageEnvelope.java
@@ -20,6 +20,7 @@ public class JsonMessageEnvelope {
     final Integer sourceDevice;
 
     @JsonProperty
+    @JsonInclude(JsonInclude.Include.NON_NULL)
     final String relay;
 
     @JsonProperty