Check _tiki.sql suffixes
Check upgraded vs new install db structure
Check in tiki.sql there is Drop Table if Exists
Check MyISAM vs InnoDB install
Check Jquery versions in Headerlib
grep external links
Check JSLint (just did the error and left the warnings )
Check the README file for manual commits
Remove any out of sync English strings
Delete secdb files from previous versions
security check
Check index.php existence
Prefs report http://doc.tiki.org/tiki-download_wiki_attachment.php?attId=71&page=Tiki13&download=y