Re: Upgrade?
If you're upgrading to Tiki 2.2 from Tiki 2.0 or 2.1, there's a small package that contains only the changed files. For any other upgrade the complete package should replace your current files (however you want to do that, by installing over (ftp/copy "overwrite when source newer", etc.) or deleting the old file tree and putting the new one in its place (saving any customized files or site content that's in the file hierarchy). Then run tiki-install.php to update the database.
-- Gary