GravityView - Modify the CSV file name

gravityview-modify-csv-filename.php

<?php

/**
 * Modify the name of the generated CSV file. Name will be sanitized using sanitize_file_name() before output.
 *
 * Requires GravityView 2.1 or newer.
 * 
 * @param string   $original_filename File name used when downloading a CSV. Default is "{View title}.csv"
 * @param \GV\View $view Current View being rendered
 */
add_filter( 'gravityview/output/csv/filename', function( $original_filename = '', $view ) {

	// A View named "Guest List" will output "Guest-List-2018-09-27-184829.csv"
	$new_filename = $original_filename . '-' . current_time( 'mysql' );

	return $new_filename;
} );