OAuth already works with Gmail POP3 accounts (so I have read - I don't use that configuration.) Check out the following article for hints. What I get out of a quick scan of it is that you first need to set the SMTP server to use OAuth, then it should be available for the POP3 server.

https://support.mozilla.org/en-US/kb/thunderbird-and-gmail#w_updating-a-gmail-account-to-use-oauth

Thanks, Lin, but I think this refers to the desktop version. When setting up, in the Android version, 0Auth2 doesn't appear, in the Authentication method box. (And, as far as I can see, the server settings pages can only be accessed on setting up the account, rather than being tweakable, afterwards, as in the desktop version. I could be wrong, here.)

If you try to clone already set up desktop settings (QR code etc) then the Android version ends up as IMAP.

I'd be delighted to learn that I've misunderstood something.

Cheers

Oops, you're right, I totally glossed over the Android part of your question. I don't use Thunderbird for Android, but I used to use K-9 Mail, which you probably know is what Tbird Android is based upon. I'm sure it's changed since then, but I do remember that all server settings were available to be edited, but some of them were buried in there in hard-to-find places.

As you note TBA doesn't support oAuth with pop3 connections.

Per the comments in the github link below. "While we're not removing POP3 support at the moment, it isn't something we want to focus on"

https://github.com/thunderbird/thunderbird-android/issues/9094#issuecomment-2842184393

Have you tried creating a Gmail app password for Thunderbird. See link below. You can use this method instead of Oauth with TBA pop3 connections. This creates a 16 digit code which you enter in TBA instead of your main account password.

https://support.google.com/mail/answer/185833?hl=en

Very many thanks, Platform34. By chance, I had stumbled upon App Passwords, last night, but thought it might be out of date. Your post reassured.

I've now tried it and, while it appeared to work, fear I've misunderstood something or done something stupid. Testing shows the following, with two mobile devices and one desktop device.

1. Email appears to send OK 2. Once email has been received on any of the devices, it won't appear on either of the others, even if it hasn't been opened or deleted.

To my, admittedly untrained, eye, this looks more like exaggerated IMAP behaviour than the POP behaviour I was seeking. On desktop, I've set "delete from server" to 30 days, so I don't think it's that.

Have I done something silly?

Ah...Just found material about Gmail's need for "recent:" With multiple devices. Solved, I think.