[Dovecot] MUA notifications on new mail in a new folder?

[Timo Sirainen]

On 20.1.2010, at 23.17, Kārlis Repsons wrote:
> What exactly? Does a MUA gets notified about both the new folder and mail?
> 
>> But this is more of a client and/or IMAP protocol problem. Nothing
>> Dovecot can do about it.
> Could you, please, explain why can it be a protocol problem? 

In IMAP a single connection can select a single folder. When it has selected the folder, it gets notifications about changes to that one specific folder. When it issues IDLE command, it gets those notifications immediately.

There are no automatic notifications about changes to non-selected folders. There are two ways clients can get these:

a) They'll create n connections to select n folders and issue IDLE command for them. This won't work if there are a lot of folders. For example Dovecot limits the number of connections/ip to 10.

b) They'll issue STATUS commands to ask for folder state every n minutes.

Typically it seems to be a combination of a) and b). There is a NOTIFY extension that supports notifying changes to non-selected folders, but there are very close to zero servers and clients supporting it. Dovecot will, some day..