I would try to help, but I cannot use Change Quote right now because it must be updated to work with the current version of Thunderbird, so I won't be able to use it to figure anything out. Other support volunteers may have the same problem.

Are you saying that addon doesn't work with version 128.7.1? If so, that's not accurate, as I'm using it without any issues, I just can't get the reply header looking the way I want. I have the following in the custom reply header box: On %D, %M %d %Y, %y %h %i %a wrote: If I understand the documentation correctly, that should give me On Sat, Mar 8 2024 7:54PM Bob Cavanaugh wrote: That's not what's happening though, I just get all the symbols in my reply header instead.

Try it with the settings in the attached picture. For the Customized format, use %D %M %d %Y, %h:%i %A

Clearly you are having issues. I had to install the addon to see where you were going very wrong. But basically the developer has documented the process here https://github.com/caligraf/ChangeQuote/wiki and you apparently have not followed the instructions.

You customized date information goes in the customized date box and you select to use it, not in the customized header box.

What goes in the header box will be on %%5 %%1 wrote

The current release is 136.0.