I can venture a guess. IMAP is an industry standard. Documented, validate-able (i.e. is this IMAP command correct or malformed, is the response correct).
It's a "common language" that lets mail services and mail apps to interoperate: Thunderbird, K9 Mail, Windows Mail, Samsung Email, etc. <-> iCloud, GMX, AOL, Yahoo, Gmail, Yandex, etc. There is no "K9 Mail for iCloud" vs "K9 Mail for GMX" or "Thunderbird for Yandex" vs. "Thunderbird for Fastmail". For mail app developers, this is what they implement so their apps work with "any" mail service. For mail services, this is what they expose to allow "any" mail app to connect to them. And there are limitations - like we're discussing now, Yahoo servers support the "base" IMAP spec but do not support the IDLE extension. They aren't required to, IDLE is an extension, optional. There are other extensions, e.g. "MOVE" to more efficiently move messages between folders (base IMAP is "copy / delete the original") just to give you an idea. Some mail services may not even have IMAP, only POP3 (although this is rare these days). On the other hand, when the mail service and the mail app are from same company (AOL's email app, Yahoo's email app, Fastmail email app, Yandex email app, ...) - they can use some completely different way (not IMAP) to connect the two. I'm guessing that AOL / Yahoo have completely different servers for their own app(s) speaking a completely different network protocol, not IMAP, and this custom protocol, available only internally to their own apps has additional capabilities such as push mail (and very easily it's not even based on same concepts as IMAP IDLE - possibly leverages Google cloud push / Apple push since again they own both sides). And then you have cloud based email apps which first collect your email to their own servers (using IDLE or very frequent polling) and then push any changes to the device (only if there are changes, so it's battery efficient). Potentially this can be a privacy issue (and then who pays for the cloud servers if such an app is completely free?) Anyway, I don't work on K9 Mail and not going mention what app I do work on because it's not K9 and this is a K9 forum. Just think of my messages as two (or four) cents from a passer-by who happens to (maybe) know a thing or two. -- K On Sunday, September 9, 2018 at 10:34:32 AM UTC+3, Tony Gamble wrote: > > > > Yes the AOL Android app does seem to push on the account where K-9 and > Aquamail fail. > > I wonder if Kostja can work out why? > > > -- You received this message because you are subscribed to the Google Groups "K-9 Mail" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
