[GNC] Anyone noticing an issue with list messages 'un-threading'?

[Fred Bone]

On 08 January 2020 at 0:13, Adrien Monteleone said:

> David,
> 
> It’s quite all right. I think it was just noticed first that some of
> your replies were un-threaded. But as I noted also, this isn’t isolated
> to just you. (and Derek might be on to something with the Android angle)
> 
> I guess we’ll see if changing Android clients ’solves’ the problem
> from your end. That will be an interesting test.

Whether it fixes the problem will depend partly on which client he 
switches to; and it isn't specific to any one operating system anyway.

Generally,
1. Threading depends on the In-Reply-To: header, which should contain the 
data from the Message-ID: header in the message being replied to.
2. Some email clients fail to supply this header (when formatting the 
reply), in which case the threading is broken.
3. If you receive the plaintext (rather than MIME) digest, there is 
nowhere for the Message-ID: headers of the digested messages to go, so no 
mail client is going to be able to maintain threading.