[Mailman-Users] Version Error with Migrated Lists?

[Anthony Harrison]

I'm attempting to migrate a number of lists from Mailman 2.1.11 on a box
running Ubuntu 8.04.3 to Mailman 2.1.14 running on a box with Red Hat
Enterprise Linux Server release 6.2. I've installed Mailman on the Red Hat
box according to the installation guide and have successfully created a
working mailing list under it. I've added a few people to it and confirmed
that it can send and receive messages.

With a working version of mailman on Red Hat, I copied over the lists,
data, and archive directory as per the migration guides. I updated the file
permissions via check_perms -f and then ran genaliases.

Whenever I attempt to run fix_url on any of the lists, however, I receive
the following error:

Importing fix_url...
Running fix_url.fix_url()...
Loading list itsac-test (locked)
Traceback (most recent call last):
  File "./withlist", line 299, in <module>
    main()
  File "./withlist", line 277, in main
    r = do_list(listname, args, func)
  File "./withlist", line 195, in do_list
    m = MailList.MailList(listname, lock=LOCK)
  File "/usr/local/mailman/Mailman/MailList.py", line 128, in __init__
    self.Lock()
  File "/usr/local/mailman/Mailman/MailList.py", line 165, in Lock
    self.Load()
  File "/usr/local/mailman/Mailman/MailList.py", line 676, in Load
    self.CheckVersion(dict)
  File "/usr/local/mailman/Mailman/MailList.py", line 729, in CheckVersion
    Update(self, stored_state)
  File "/usr/local/mailman/Mailman/versions.py", line 54, in Update
    UpdateOldVars(l, stored_state)
  File "/usr/local/mailman/Mailman/versions.py", line 190, in UpdateOldVars
    for addr in l.posters:
  File "/usr/local/mailman/Mailman/MailList.py", line 146, in __getattr__
    raise AttributeError, name
AttributeError: posters

This seems to be related to an incorrect version number, but I have no idea
how to remedy this. Have I missed some crucial step in the migration?