In Drupal 7, when saving a title with multipule characters ,like "Cher collègue nous allons vérifier tout cela", getting this warning:
Warning: htmlspecialchars(): Invalid multibyte sequence in argument in check_plain() (line 1545 of /var/home/henry/www/worksrepo.com/includes/bootstrap.inc).
Multiple characters cannot be present in title!
How to fix it?