On 17/04/2013 10:58, Timo Sirainen wrote:
On 16.4.2013, at 2.48, Gregory Sloop<gregs@sloop.net> wrote:
In short, migrating a RHEL 5.9 server running the back-ported Dovecot 1.0.7 To: Ububtu 12.04 with 2.0.19, I believe.
Dovecot v2.0 can use v1.0's mbox/maildir files including their metadata. v2.0 should also be able to read v1.0's index files without errors.
We've a similar wish, except that we were hoping to install 2.2 on a different box (intending in our case to run Debian Squeeze instead of Ubuntu LTS). Can 2.2 (or, if not, then 2.1) also read 1.0 metadata?
(Or is 'only' 2.0 able to read 1.0 metadata? In which case we'd probably migrate through 2.0.x to 2.2, on Squeeze.)
Note on the Wiki: The Migration page http://wiki2.dovecot.org/Migration is good at describing migration 'to' Dovecot from other systems, and does suggest that Dovecot will read existing files. I think there were earlier discussions on the list about Dovecot version changes which meant that newer versions could read older versions' data, but older versions could not read newer versions' data. These aspects are not relevant for 'migrating to' Dovecot, but are worth keeping in mind for 'upgrading' Dovecot.
There is version to version upgrading advice, covering all aspects, not only which version can read what, here http://wiki2.dovecot.org/Upgrading
What I can see, from the descriptions of each version change, is that V2.x can read V1.x, but V1.2.4 or lower cannot read V2.x data. Permissions for Maildir changed, though, in V2.0 and, then for all mailbox types (it says 'creating home directories', actually), in V2.2. This latter change in 2.2 seems to be relevant for any mailboxes that will be accessed by several different users who are actually 'system users', ie, a mail service where the mailbox is 'shared', and the installation is using 'system users' (not, therefore, using 'virtual users', if I have understood correctly).
This info is (surely) fully understood already by all the serious mail-server users on the list, but I wonder if it might be helpful to spell it out for less confident users who are getting up to speed with these aspects. If the text I've written above is correct, shall I add it to the upgrading page of the Wiki, so that there is a definitive answer to the query which version(s) read what?
regards, Ron