@Override public AttributeSchemaImpl upgradeAttribute(AttributeSchemaImpl newAttr) throws UpgradeException {
  return updateDefaultValues(newAttr,Collections.singleton(OLDEST_VERSION));
}

@ Override public AttributeSchemaImpl upgradeAttribute ( AttributeSchemaImpl newAttr ) throws UpgradeException { return updateDefaultValues ( newAttr , Collections . singleton ( OLDEST_VERSION ) ) ; }
this is called when the service is added for the first time and it will change the default install value of an attribute .
