diff --git a/src/pynxtools/data/NXtest.nxdl.xml b/src/pynxtools/data/NXtest.nxdl.xml
index 01e39214d..04d9dd1b8 100644
--- a/src/pynxtools/data/NXtest.nxdl.xml
+++ b/src/pynxtools/data/NXtest.nxdl.xml
@@ -13,8 +13,9 @@
         <field name="program_name"/>
         <field name="definition">
             <doc>This is a dummy NXDL to test out the dataconverter.</doc>
-            <attribute name="version"/>
+            <attribute name="version">
                 <doc>This is the version of the definition.</doc>
+            </attribute>
             <enumeration>
                 <item value="NXTEST"/>
                 <item value="NXtest"/>