I have been doing some testing with the recent support for IMAP IDLE (RFC 2177) or Push E-mail using IMAP.
It might surprise people but IDLE is currently supported by most IMAP servers. I tested with Cyrus, Exchange, Isode M-Box, Courier and Dovecot. The only one that didn’t worked with the current solution in tinymail was Dovecot. I did see the right EXISTS coming through, it seems that the UID FETCH that follows gets wrong information. I really haven’t in depth looked at this though. So I’m not yet blaming Dovecot for this. It might very well be a discrepancy in how I’m using IDLE.
ps. I’m tracking the testing of IMAP IDLE & Push E-mail here.