Yahoo fixes their implementation of IMAP, finally

Back in January, I wrote about a Yahoo Mail issue that affected smartphones such as Windows Phone and the iPhone. To quickly summarize, whenever a smartphone checked for new Yahoo mail, the server would transmit more information than needed. While not a huge problem on desktops connected to broadband, it was huge in the mobile space – a space in which carriers snipe bandwidth hogs and users oblivious to their data usage and monthly allowances.

After discovering the problem, I made it habit to log into Yahoo every few days, checking their “imapgate” software version. Today, I was pleasantly surprised to see they had upgraded from 0.7.65_12.286037 to 0.7.65_14.298026 fixing the issue. I can’t say when this happened precisely, but I suspect it was rolled out earlier in the week, to coincide with the new Windows Phone update. (Of course, the update never shipped.)

Anyway, I re-tested their FETCH capabilities and lo’ and behold – the bug was fixed!

Here's my phone requesting some message information:

A8 FETCH 134:135 (UID FLAGS BODY.PEEK[HEADER.FIELDS (MESSAGE-ID)]).

... and here's Yahoo's shiny new reply!

* 134 FETCH (FLAGS () UID 260 BODY[HEADER.FIELDS (MESSAGE-ID)] {52}
Message-ID: <4D7940FD.5030509@withinwindows.com>
)

If you recall, Yahoo previously sent back the entire message header. Now, only the requested information (Message-ID) is returned. If you write IMAP software that access Yahoo servers, let me know if you see any other changes good or bad.