IMAP synchronization question

Andrew Sutherland asutherland at
Fri Aug 23 22:36:48 UTC 2013

On 08/23/2013 10:47 AM, Tanstaafl wrote:
> Did Mozilla do any formal testing on dovecot and/or other IMAP servers?
> Meaning... do we know if it is known to work flawlessly (or at least 
> well) with Dovecot?

If you're using dovecot, you've probably been using CONDSTORE with 
Thunderbird since 3.0.  Dovecot got CONDSTORE early (v1.2) and most 
modern IMAP servers support CONDSTORE/QRESYNC including the 
server (Zimbra), dreamhost which I know both myself and bienvenu 
use/used (dovecot 2.1 currently), and (Cyrus). It's really 
only the big webmail providers with custom server implementations and 
IMAP mappings that were behind the times. (gmail, yahoo, etc.)

Which is to say, it works, but it's not surprising there might be some 
bugs such as the one in question.

For research, the implementation bug was and the commit was

> Also, is this the pref you meant:
> mail.server.default.use_condstore;true  ?

Mail server preferences have a default and per account settings. The 
preferences are:


> And if it is set, it is enabled for all accounts?

If the preference is enabled for the server (by default it is for all 
servers) and CONDSTORE is advertised as an IMAP CAPABILITY, CONDSTORE 
will be used.  The capabilities should be obvious in an IMAP protocol 
trace, or on linux you can do something like this:

openssl s_client -connect HOSTNAME:993

And then type "A1 CAPABILITY" and it should spit back the capabilities.  
Some servers don't provide the full capability list until after the user 
has authenticated, however.


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