I have MySQL 4.1.7 and when trying to upgrade from 2.6.6 to 2.6.7 or 2.6.8rc2 I get an error. The error is different depending on which of the two versions I am upgrading to.
For 2.6.7 it is:MySQL Error: #1273 (Unknown collation: 'utf8'): ALTER TABLE fud26_action_log CONVERT TO CHARACTER SET utf8 COLLATE utf8
For 2.6.8rc2 it is:MySQL Error: #1270 (Illegal mix of collations (utf8_general_ci,IMPLICIT), (latin1_swedish_ci,COERCIBLE), (latin1_swedish_ci,COERCIBLE) for operation 'replace'): UPDATE fud26_ses SET action=REPLACE(action, 'http://bb.prohost.org/mm/', '')