diff --git a/src/main/resources/message_schema.xsd b/src/main/resources/message_schema.xsd
index b902bcc..4151e4b 100644
--- a/src/main/resources/message_schema.xsd
+++ b/src/main/resources/message_schema.xsd
@@ -18,7 +18,7 @@
 			<xs:element name="MetaData">
 				<xs:complexType>
 					<xs:sequence>
-						<xs:element name="Sender" type="xs:string" />
+						<xs:element name="Sender" type="xs:long" />
 						<xs:element name="Recipient" type="xs:long" />
 						<xs:element name="Date" type="xs:date" />
 						<xs:element name="State" type="xs:boolean" />