I also came here to write about K9. It's open source, it works well, it supports encryption (with the OpenKeychain app). I don't have much more to ask to it. I don't think it's worth investing on a mobile Thunderbird but to be fair, I'm pretty happy with desktop Thunderbird too. They could stay in maintenance mode and make sure that it keeps running on any new OS version it's released.

If I can wish for something, fix this bug from 2009 https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/3... (but originally from 2007)

I have a similar sentiment towards Thunderbird. Every once in a while I try using other Linux desktop clients but I always go back to Thunderbird. Feature-wise I don't miss anything. My biggest problem are various long-standing bugs and occasional crashes. Each time it crashes I wonder whether that is something that might be exploitable by a specially-crafted email.

For me, Mailspring (successor of Nylas N1) works, but it does use Electron... (Therefore IMO not suitable for mobile, but I wasn't suggesting that either way.)

+1 k9 is really good, I think it would be a pity to split thunderbird resource on mobile front, maybe they can share resource (low level protocol libraries?)/public relation (i.e mutual refering) so that they core developers can focus on what they're good at.

My opinion is that developing an app for mobile and one for desktop is really two different set of skills and it's not because you've made an awesome desktop app that you will produce an awesome mobile app, vice-versa.

A big problem with K-9 (and open-source clients in general), is detailed in this thread: https://github.com/k9mail/k-9/issues/655

Unfortunately, this is not so much a problem with the quality of the client, but rather with the strangle-hold of big providers over the email system, but users will inevitably complain to the client developers about it.

This is a feature, not a bug. Google comes up with ideas, sure, that doesn't mean all projects have to support it. There is nothing wrong with SSL IMAP auth.

> This is a feature, not a bug.

Fully agree. My point was that most users will disagree with you and I, or simply not really care to consider our argument. And that informs their choices.

Quote from the article:

> When I asked what that might look like the answers were uniformly along the lines of: “There is not a really good, open source, Email client on mobile...

People encountering issues with proprietary crap like Google's XOAUTH2 implementation could well be contributing to this view.

SSL IMAP auth prevents bystanders from watching the password. Google's auth goes further, the IMAP client doesn't have to store your password at all. Instead client stores an app-specific password-like string instead, one with limited rights), which is a big improvement IMNSHO.

Which is different from XOAUTH2. The "less secure apps" listed in google still list ones using app-specific passwords.

If you look at how, e.g. Fastmail solves this[0] (and other services do the same or similar), it's a nice example of something that's both secure and supports any client without requiring the client to do anything specific to their service.

[0] https://www.fastmail.com/help/clients/apppassword.html?u=069...

Replying to cvwright:

That feature is presented by Google as an alternative "for less secure apps". If you're using a client that Google considers to be "less secure", you also have to explicitly enable support for "less secure apps" in settings, in addition to that. This setting may not even be available to you if you're not on @gmail.com and your domain administrator has disabled it (which Google recommends they do).

From the Github issue linked above, apparently Google supports something similar: https://support.google.com/accounts/answer/185833

Thunderbird doesn't support this either, does it. I thus don't see the relevance of this argument.

It does.

I had been using K9 since 2010 or so, since there were only few mail clients supporting multiple accounts, but I always found it rather confusing to navigate around.

Especially the settings, there are Global settings, account settings, folder settings but didn't always show up in the menu.

The ergnomics are terrible and the search engine is barely useful.

It's still the lesser of all evils on mobile though.

I'm the sort of person who lives on the cli, I've been considering trying to port some of my emacs/gnus setup to my android device. I wonder how well it would work?

Check out Termux. I'm running Emacs on both my phone and tablet on occasion.

https://wiki.termux.com/wiki/Main_Page

Note: also works on new-ish Chromebooks (so you don't necessarily need to enable developer mode to work offline).

You must hook a real keyboard up, right?

I can't even imagine trying to run emacs on an on-screen touch keyboard.

Hacker Keyboard will allow you to achieve a lot. All, with all CLI programs? That I do not know. There is a learning curve either way. You can also SSH out of your machine with a terminal app (recommend to look into Mosh) if you got a good internet connection such as 4G/LTE or WiFi. Then you can run e.g. Mutt remotely. Use with tmux and never close it.

As for hook up, there's BT and USB OTG.

Blackberry ftw ;)

Since we're listing issues with K9: It's pretty easy to setup if you know what you're doing, but the lack of any sort of autoconfig for non-Gmail mail servers make it very difficult to give it to a normal user and have it just work. Thunderbird has a standard autoconfig file to do this, and there is an open issue on K9 to add support for the same format, but it's been open and stagnant for years[0]

[0] https://github.com/k9mail/k-9/issues/865

K-9 mail is great, but just one part of the replacement.

I've yet to find a very good contact list for Android.

... and a calendar that works remotely as good as the one of Thunderbird (Lightning).

For calendar on Android, have you tried Etar? https://f-droid.org/en/packages/ws.xsoh.etar/

Thanks for the hint! I wasn't aware of that package. I'll try it.

K9 is excellent, and has good PGP support as well. Been using it for the past two years without any trouble.

K-9 is slow and has an ancient UI. I hope that they will finish the rewrite to Material UI any time soon.

You've gotten a lot of recommendations for K9, which I also like. But I went with Aquamail on Android, which has worked really well for me and I'm very happy with it. Actively developed and maintained, and very slick interface.

I'm a big supporter of open source software. However, I pay for a copy of Aquamail. I also paid for a version of K9, in order to support the developer. Aquamail is a good product and the developer is continuously improving it. I would hate to live in a world where your only options for email would be to use one of the big providers (gmail, office 365, etc).

BTW, Aquamail is free, just not open source. The free version has a few limitations, I think, like a non-changeable signature.

Non-free and thus irrelevant.

It's good, some options are placed at very counter intuitive places and it would be nice if they'd slap some material design on top of it. Other than that it's pretty nice indeed.

+1 for K9. I wish it or something as good were available for iOS.