Enabling mod-sequences

[Luca Bertoncello]

Hi list!

I have Dovecot 1.2.9 from Ubuntu repositories on my server.
Now I installed Horde and it give me sometimes the error "Mailbox does not
support mod-sequences".

Well, I must say, that I didn't know these mod-sequences, but I can' know
all...

Well, the question now is: how can I enable the support of the mod-sequences
on the mailboxes of my Server?

I searched in the Dovecot-Wiki, but I didn't found anything...

Thanks a lot for your help
Luca Bertoncello
(lucabert at lucabert.de)