soliver1971 on "MySQL version control failes during upgrade to 4.0"

The tech support told me to change the DB_HOST in the wp_config.php to

/** MySQL hostname */
define('DB_HOST', '127.0.0.1:3350');

then

db_version returns "5.0.51",
mysql_get_server_info() returns "5.0.51_InodeWebhosting"

Finally the update worked.

Thanks for all the help!
Oliver