diff --git a/resources/schema/inventory.xsd b/resources/schema/inventory.xsd
index 4311d8c..a91d96a 100644
--- a/resources/schema/inventory.xsd
+++ b/resources/schema/inventory.xsd
@@ -116,7 +116,7 @@
     <xsd:attribute name="id" type="xsd:int"/>
     <xsd:attribute name="sloleksId" type="xsd:string"/>
     <xsd:attribute name="sloleksKey" type="xsd:string"/>
-    <xsd:attribute name="type" use="required"> <!-- types of headwords allowed; hmm, probably should standardise allowed settings -->
+    <xsd:attribute name="type"> <!-- types of headwords allowed; hmm, probably should standardise allowed settings -->
       <xsd:simpleType>
         <xsd:restriction base="xsd:string">
           <xsd:enumeration value="single"/>