Any interest to implement RFC4978 (IMAP COMPRESS)?

[Rob Mueller]

>> For low bandwith connections this could be useful but I don't know if
>> that's a typical case nowadays. Together with the IMAP IDLE command it
>> should be fine for mobile devices...
>>
>> [1] http://tools.ietf.org/html/rfc4978
>
> I thought that this was supported in 2.3.16.

It's definitely in CVS, not sure what released version it's in (check the 
changelog?). We use it at FastMail.

http://blog.fastmail.fm/2009/05/01/help-test-proxy-to-improve-imap-performance/

Rob