Issue passing dates to datepicker in Ninja Forms

filter_ninja_forms_forms_display_datepicker_args_not_working.php

//Customise Datepicker on contact forms
function nf_datepicker_modify_script( $args ){
	//for a list of arguments which can be used here, see the options here http://api.jqueryui.com/datepicker/
	$args['dateFormat'] = 'mm/dd/yy';
	$args['minDate'] = '06/15/15';
	$args['minDate'] = '10/15/15';
	return $args;
}
add_filter( 'ninja_forms_forms_display_datepicker_args', 'nf_datepicker_modify_script' );