That's exactly what I do at the moment.

I did not expect it to be a possible feature within the program but wondered if an outside script could be provided to do this
(if there was a demand for such a feature)  

Occasionally I forward an email conversation (of many individual messages) to another party. So
I need to tell them to start reading the whole email from the end
.

It would therefore be useful if there was a way to reverse the order of the separate messages.

If you are adding individual message files as attachments they will appear in the order in which they are listed when you send them, at least they did in a test message I just sent to myself. 

In case you didn't know, there is a drag and drop method of adding message files as attachments.  You can drag from a folder window and drop into a new message attachment pane.

I'm not using attachments.

I'm referring to something like this (simplified)


On 16 Mar 2017 at 22:00, Fred wrote:
From:  Fred
To: Jim
Subject:           Re: Test
> Goodbye
 
> On 16 Mar 2017 at 21:00, Jim wrote:
> From:  Jim
> To: Fred
> Subject:      Test
>> Hello

The only way I know of the do what you would like is to copy the content to an editor like Notepad, manually manipulate it, then copy it back to a message.