First experience with RC 4 after update from 1.7 (General)
It may be an smart to run these queries as well:
UPDATE mlf2_entries SET text = REPLACE (text,'[img|left]','[img]');
UPDATE mlf2_entries SET text = REPLACE (text,'[img|right]','[img]');
This makes images from v. 1.7 visible as the [img|left] and [img|right] tags are not supported in version 2.0.