diff --git a/src/main/resources/com/solab/iso8583/parse/j8583.dtd b/src/main/resources/com/solab/iso8583/parse/j8583.dtd
index 90d53cf..f7a3011 100644
--- a/src/main/resources/com/solab/iso8583/parse/j8583.dtd
+++ b/src/main/resources/com/solab/iso8583/parse/j8583.dtd
@@ -10,6 +10,7 @@
 
 <!ELEMENT parse ( field+ ) >
 <!ATTLIST parse type NMTOKEN #REQUIRED >
+<!ATTLIST parse extends NMTOKEN #IMPLIED >
 
 <!ELEMENT field ( #PCDATA ) >
 <!ATTLIST field num NMTOKEN #REQUIRED >