TYPO3 Core

If you create an new TYPO3 4.5 installation, then you´ll notice, that "setDBinit" and "forceCharset" are not set, because since TYPO3 4.5 those values have a default setting if not set in localconf.php. If the upgrade wizzard sets one or both values to an empty sting, then your TYPO3 4.4.x installation has´nt been setup correctly to use UTF-8 (e.g. not all table-collations set to utf8_general_ci).

In TYPO3 4.4.x, both "setDBinit" and "forceCharset" must be setup as described in the TYPO3 wiki (http://wiki.typo3.org/UTF-8_support). If this is not the case, that you have to convert your database to UTF-8 before upgrading to TYPO3 4.5

It all worked fine (converted DB before upgrade, changed collation of columns and also of database). It's just that there was no setDBinit-setting before, I then adjusted the DB and upgraded TYPO3 - and at that point the wizard inserted those two settings into localconf.php - but with an empty string (which prevents the UTF-8-default). Removing them worked. I'm just saying that not writing empty strings into localconf.php at all (and people knowing there is a new default which requires DB-adjustment) might be an easier way.