I now have
BlogEntry::$allow_wysiwyg_editing = false;
in _config.php and the blogs now display nicely in the overview page and the editor comes with bbcode instead of wysiwyg.
But when i click "Read the full post" on any article i see all the html-tags in the output. This is annoying. What have i done wrong?
Please help - this is the last issue in the 2.4 upgrade dilemma.