Since #Joomla 3.8.8, uploading flash files (swf files) and allowing the "flash" (application/x-shockwave-flash) mime type for uploading have been removed from the default settings of new Joomla installs. Allowing these 2 things is a security concern if there is not first a proper review of their contents and programming. How to remove flash file extensions and mime type from the allowed methods of uploading is what today's #maintenancemonday is all about.