Feature #97


Added by Mathias Steiger about 10 years ago. Updated 6 months ago.

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For ages, IMAP IDLE has been missing in Sylpheed.

I combed the internet for this and apparently it was bugreported before, around 2008. No one of the developers ever answered that bugreport, or why IMAP IDLE is not even considered in the features. Around that time, someone even posted a patch, but it was discarded.

If you look online, missing support of IMAP IDLE is the number 1 reason for people to not use Sylpheed. It is /the/ biggest drawback, just consider this ordinary mail setup:

You have 2-5 Mail accounts, one private, one for work, another for work maybe, one for online registrations as a spamcatcher, maybe one at google because your phone requires a google account, maybe another one for another workplace, one for your open source projects maybe, and so on.
Your mail is 'cluttered', you have a lot of folders, just because you need to archive things and keep them in order easily accessible from everywhere. Because of this, each poll of your mail accounts takes a lot of time.
You need mail for work and need to receive new messages by the minute. Because of this, you have to set Sylpheed to poll as frequently as possible. Now here is the catch: If you set the polling frequency too low, people at work will get offended because your plus 10 minute delay disrupts communication. If it takes you 5 or 10 minutes to just reply to a one-liner with a one-liner, 5 times in a row, it is not nice. That's how people work nowadays though, they don't bother to use IM for it because it is unecessary and more complicated. I am a sysadmin and 10 minutes not knowing that the VPN or servers went down is crucial. Lots of other professions are no different.
On the contrary, if you set the polling frequency too high, the mailservers will get offended and at least one will block your poll every once in a while, causing Sylpheed to freeze even longer than usual (which means it is disabled for minutes).
Additionally, at every poll, you can't access your mail for a cuple of seconds (usually 3-15) and can neither send nor write messages. This can heavily disrupt workflow, especially if you write 20 messages or so within two hours.

Suffice it to say, if you want to use Sylpheed for work, you have a considerable problem. IMAP IDLE solves this by instantly notifying you about new messages and removing the unecessary block of using Sylpheed during polls. IMAP IDLE has drawbacks, but honestly, the advantages outweigh the disadvantages by far.

This feature is so important, I would do it myself if I had time and no one more qualified is available.

Or is there some questionable resentment against IMAP IDLE by the developers?


Updated by Hiroyuki Yamamoto almost 10 years ago

  • Priority changed from Urgent to Normal

IMAP IDLE support is frequently requested, and I also want to support it.
But it requires some re-design of the handling of IMAP network session.
(In the current implementation, every communication requires user interaction)
Anyway, I will add IMAP IDLE support in the TODO list.


Updated by X. W. almost 9 years ago

Dear Mr. Yamamoto,

any updates on this?

Unfortunately it does not even seem to be on the TODO list:


This feature would be much appreciated.



Updated by X. W. almost 9 years ago

Dear Mr. Yamamoto,

please also have a look at this:



Updated by Mathias Steiger almost 9 years ago

I don't want to be pessimistic, but Sylpheed has been at a standstill for many years.

I started writing an ugly hack to get solid & stable IMAP IDLE new mail notifications working, not to support the whole RFC and what not I don't care about. I already invested 1.5 hours and it seems it needs another 2 or so. I hope I get this done soon.

To me it seems this issue is extremely critical to the vast majority: you get a mail -> you see the mail, you send a mail -> the mail sends. The polling and lack of IDLE breaks both behaviors to some more significant degree.

Lemonade Profile is targeting minorities, a nice but not required addition.


Updated by X. W. almost 9 years ago

Lemonade Profile is targeting minorities, a nice but not required addition.

But the IMAP NOTIFY extension in addition:

would be even better than just IMAP IDLE, wouldn't it ;)?


Updated by X. W. almost 9 years ago


By the way, they are also talking about this on the Claws Mail bug tracker, see:



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