Hi all,
Just did the 5.5 upgrade and I got errors on reboot.  Couldn't read them all as they scrolled past.  But I have found some serious problems in trying to use WEBMAIL:
I tried to access an email aaccount and I get the following errors:
A fatal error has occurred 
object(db_error)(7) {
  ["error_message_prefix"]=>
  string(0) ""
  ["mode"]=>
  int(1)
  ["level"]=>
  int(1024)
  ["code"]=>
  int(-24)
  ["message"]=>
  string(24) "DB Error: connect failed"
  ["userinfo"]=>
  string(86) " [nativecode=Access denied for user: 'horde@localhost' (Using password: YES)] ** Array"
  ["callback"]=>
  NULL
}
[/home/httpd/html/horde/lib/Prefs/sql.php : 102]