Change GravityExport Lite export filename

gk_custom_excel_filename.php

<?php // DO NOT COPY THIS LINE

/**
 * Change GravityExport Lite export filename.
 *
 * Hook: gfexcel_renderer_filename          ← all forms
 *       gfexcel_renderer_filename_{ID}     ← one specific form
 *
 * @param string $filename  The filename generated by the plugin.
 * @param int    $form_id   (Since v1.6) ID of the form being exported.
 *
 * @return string           New filename. MUST keep the .xlsx extension.
 */
function gk_custom_excel_filename( $filename, $form_id = 0 ) {

    // 1 ) Pick the base name you want to see on every file
    $base = 'Custom-Filename';                 // ← change this to anything

    // 2 ) Build the date suffix in “YYYY MM DD” (e.g. 2025 04 25)
    $date = gmdate( 'Y-m-d' );              // gmtime avoids server-TZ surprises

    // 3 ) Return the final name
    return sanitize_file_name( "{$base}-{$date}" );
}
add_filter( 'gfexcel_renderer_filename', 'gk_custom_excel_filename', 10, 2 );

/*
 * Want it for just one form?  Replace the last line with, e.g.:
 * add_filter( 'gfexcel_renderer_filename_42', 'gk_custom_excel_filename', 10, 2 );
 * …where 42 is your form’s ID.
 */