User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.81 Safari/537.36 OPR/80.0.4170.63

Steps to reproduce:

Getting to Accounts -> add Account -> Chat-Account

Actual results:

No "SMTP/IMAP"-Chat-Protocol

Expected results:

The choice of "SMTP/IMAP"-Chat-Protocol -> use existing email account AND add email account

I think Delta Chat uses chat-over-IMAP (COI), see https://www.coi-dev.org/

Delta Chat has some info in their implementation: https://github.com/deltachat/deltachat-core-rust/blob/master/standards.md#standards-used-in-delta-chat / https://github.com/deltachat/deltachat-core-rust/blob/master/spec.md#chat-mail-specification

I thought we had a bug for this already but couldn’t find one!

https://www.coi-dev.org seems to be having cert issues, but https://github.com/coi-dev/coi-specs still works.

DeltaChat was started in 2017, respective late 2016 - and its a derivate, an appreciated fork for the open source protocoll and idea:

In mid 2016 the method to chat over e-mail servers was described in the study by Adam (2016).

and also it was in the news magazines announced, e,g, here in the year 2014
https://www.pro-linux.de/news/1/21822/poptastic-verschl%C3%BCsselter-chat-%C3%BCber-pop3.html

and has been invented and implemented originally in the Spot-On Encryption Suite ten years ago:
https://github.com/textbrowser/spot-on

see also described in the documentation:
https://github.com/textbrowser/spot-on/blob/master/branches/trunk/Documentation/Spot-On.pdf

The protocol is named POPTASTIC. It handles Chat over IMAP, POP3 and SMTP.
The original implementation uses RSA keys and McEliece Keys.
(The derivative mobile Apps use GPG, but not yet the standard GPG keys but rPGP from Rust Language, and is not accoding to the Standard GPG yet. Means you cannot use existing GPG Keys to be imported in the mobile app).

Ideally the future proof McEliece Algorithm is used for chat over email servers with the POPTASTIC Protocol.
That means it can be hybrid with Spot-On Application, which handles McEliece Keyes.

RSA as algorithm is obsolete since 2016 according to NIST.

Smoke Messenger makes RSA keys interoperable with McEliece Keys.
https://f-droid.org/de/packages/org.purple.smoke/
Ideally Encryption experts proove - based on this inplementation- , if GPG with RSA can also be compatible with McEliece,
If not, the suggestion is to use only the future proof McEliece Algorithm as key.

The Delta App for POPTASTIC Chat then needs to adjust to

1. standard GPG keys (next to rPGP keys) and
2. also to handle McEliece Keys.

For Thunderbird this thread can be cosed as this suggestion for implementing chat over email-server accoding to the POPTASTIC protocol has been valid and more detailed here (above specs links even dont work):

please continue here:
https://bugzilla.mozilla.org/show_bug.cgi?id=1777771