Email submitted converted in UPPERCASE

Hello,
I found old topic here regarding the possibility to convert all user input to uppercase in notification emails. I looked https://contactform7.com/special-mail-tags and my code in functions.php is the one below but it doesn’t work.
Where am I wrong?
Thx

add_filter( 'wpcf7_mail_tag_replaced',
 
  function( $replaced, $submitted, $html, $mail_tag ) {
    if ( is_string( $submitted ) ) {
      $replaced = strtoupper( $submitted );
    }
 
    return $replaced;
  },
 
  10, 4
);

N.B.: I also tried with !empty instead of is_string

• This topic was modified 2 years, 11 months ago by enricotv.
• This topic was modified 2 years, 11 months ago by enricotv.
• This topic was modified 2 years, 11 months ago by enricotv.