[otrs] Upgrade OTRS v. 2.0.4 to v. 2.2.3

Hello, we have a bit older installation of OTRS (v. 2.0.4 from the sources) and want to upgrade to v. 2.2.3. Can this be realized in one step or do I have to install some versions beetween (e.g. 2.1. an than 2.2. etc.) Has anyone expierence in such a major upgrade, especially with possible problems with the database (mysql) etc. I have found this post in this month with very helpful hints: http://lists.otrs.org/pipermail/otrs/2007-October/020536.html Is there somebody having also any other experience - any feedback is welcome! Thanks! Best wishes, Ivan