'boolean(1)' ); private static $defaults = array( 'UseCDN' => 'No' ); public function updateCMSFields(FieldList $fields) { $fields->addFieldsToTab('Root.FontAwesome', array( OptionsetField::create('UseCDN', 'CDN for loading assets?') ->setDescription('Depending on hosting, your viewers may or may not get better performance using a CDN') ->setSource(array( true => 'Yes', false => 'No' )) )); } }