Add-on not compatible with Thunderbird

Using Thunderbird (portable) Versions 141.0 and 142.0.

I copied Thunderbird version 141.0 from an NTFS SSD on to a removable USB stick so I could use on remote laptop. I noticed that the Allow HTML Temp add-on was disabled, so I tried the usual 'find an alternative'. This showed there was an updated add-on 10.0.8 which I tried to install. This failed saying it wasn't compatible. I even tried downloading the add-on file and installing it, this failed in the same manner. See screen clip. The USB stick is formatted as ExFAT.

Today I noticed there was a Thunderbird update available to 142.0 so I took a backup of another Thunderbird instance which is on an NTFS disk where I keep my hobby accounts. I continued with the update to V142.0 and started it up. Allow HTML temp was found to be disabled, so I went through the 'find an alternative' procedure. This failed in the same mode. See the next screen clip.

So for the hobbies Tbird instance, I restored it from the backup copy I had taken, and the plugin worked again.

Are you able to help please? I use this plugin all the time.