As @[deleted]01 and @[deleted] mentioned, the problem is, that the code is sanitized in different locations, you have to adjust:js/redactor-osticket.phpinclude/htmLawed.phpinclude/class.format.phpIf you need empty tags, classes and styles you have to adjust these files, too.Here you can download the API instructions for redactor 10.2.5Here you can find the instructions for HTMLawed