require_once(/var/www/html/filter/tex/filter.php): Failed to open stream: No such file or directory in /var/www/html/question/type/stack/stack/mathsoutput/mathsoutputfilterbase.class.php on line 21

filter/tex/filter.php has been moved to: filter/tex/classes/text_filter.php in:
moodle/moodle@29e7140