im not aware of any free hosting 'free upgrades' besides a disk space increase if you qualify for it.
to qualify for that you must:
-have an account at least 7 days old.
-be using at least 75% of your current space.
-all files must abide by the terms of service and be used by your website.
-zipped/file storage is not allowed.
but staff will need to review your website before approving or denying your request.
there might be something im not aware of that staff can chime in about.