Version 1.5.3.1 is a security upload that fixes a vulnerability with the file upload and the access of files. You should update to this latest version.

The version has the following changes:

• Improved the file upload class so that file cannot be uploaded without passing the check of extensions and mimetypes successfully. See details on GitHub: https://github.com/typemill/typemill/issues/325.
• Improved the htaccess so no access to certain file types is possible anymore.
• Fixed errors with shortcodes that do not use any attributes.
• added update for translations into NL.
• Improved cypress tests.

Along with the usual update of the folder system within your typemill installation, you should also update your htaccess file. Please look for the block "FILE/FOLDER PROTECTION" in your htaccess and update it with this rules:

# FILE/FOLDER PROTECTION

RewriteRule ^(.*)?\.yml$- [F,L] Rewriterule ^(.*)?\.yaml$ - [F,L]
RewriteRule ^(.*)?\.txt$- [F,L] RewriteRule ^(.*)?\.example$ - [F,L]
RewriteRule ^(.*)?\.git+ - [F,L]
RewriteRule ^(.*)?\.md - [F,L]
RewriteCond %{REQUEST_URI} !/index\.php
RewriteRule ^(.*)?\.ph - [F,L]
RewriteRule ^(.*)?\.twig - [F,L]
RewriteRule ^(media\/tmp\/) - [F,L]