Query?
You use an email client or mobile device that composes and sends new messages in Plain Text format. You need to ensure that Exclaimer will still be able to append a signature.
Answer
When Exclaimer receives messages in Plain Text format, it checks if a signature needs to be applied and - if yes - automatically converts them to HTML format, before applying an HTML signature.
If a Plain Text message does not require a signature, it is not converted to HTML format.