ACF Advanced Forms - Custom Reply-to

core-emails.php

<?php

// add this to `core-emails.php` file in the ACF Advanced Forms plugin ~mj

// From header
    $from = af_resolve_field_includes( $email['from'], $fields );
    $replyto = af_get_field( 'email');
    $headers[] = 'From:' . $from;

// only have reply-to to Customer if it's admin
// email address receiving the email; otherwise, the customer will have normal reply-to message ~mj
    if($email['recipient_type'] == 'custom') {
        $headers[] = 'Reply-to:' . $replyto;
        $headers[] = 'Bcc:' . $recipient;
    }