Signature 365 can apply signatures to all email except the following:
- Automatic replies (also known as out-of-office replies)
- Appointments (including meeting invites)
In respect of encrypted and digitally signed emails:
- Client-side signatures are supported. Signatures are added to email before email is encrypted or digitally signed.
- Server-side signatures are not supported. The email flow remains the same. Encrypted or digitally signed email will flow via the Signature 365 service, but no signatures will be added. When using both server-side and client-side signatures, email with a client-side signature added by the Signature add-in for Outlook will not flow via the Signature 365 service.