diff --git a/src/main/java/org/gcube/resourcemanagement/model/reference/properties/ValueSchema.java b/src/main/java/org/gcube/resourcemanagement/model/reference/properties/ValueSchema.java
index 13947db..5b5d869 100644
--- a/src/main/java/org/gcube/resourcemanagement/model/reference/properties/ValueSchema.java
+++ b/src/main/java/org/gcube/resourcemanagement/model/reference/properties/ValueSchema.java
@@ -69,7 +69,7 @@ public interface ValueSchema extends GCubeProperty, ValidatedTypedProperty<URI,S
 	 * An URI containing a schema used to validate/interpret the content of the value. 
 	 * It is only an informative field. The validation is charge of the client.
 	 */
-	@ISProperty(description = "An URI containing a schema used to validate/interpret the content of the value. It is only an informative field. The validation is charge of the client.", mandatory=true, nullable=false)
+	@ISProperty(description = "An URI containing a schema used to validate/interpret the content of the value. It is only an informative field. The validation is charge of the client.") //, mandatory=true, nullable=false)
 	@Override
 	public URI getSchema();