Hello Marco,
the screen shots that you show above are in the style of the r12.9 user interface, which suggests to me that some or all of the r12.9 CSS and r12.9 form definitions are still either in your browser cache or present in your site\mods.
Clear your browser cache first.
If that doesn't help, take a backup 'zip' of the site\mods folder, then delete all .htmpl and .css and other files out of site\mods - the contents of 'site\mods\majic' are probably OK to retain, but remove everything else, including '.js' and '.html' - clear your browser cache again, restart the Service Desk Manager service on your upgraded host, and see what you get?
Regards,
James