One of the main reasons for its security is that it allows you to either disable the display of HTML messages or set the program to prompt you before displaying such messages. This may be necessary because HTML messages are often used by e-mail viruses to automatically run attachments. Delta Mail is designed to be portable so it does not require installation on computers, which don't have your e-mail account set up. It can serve as a LAN e-mail solution because it can automatically encrypt all outgoing messages using very powerful encryption, which does not require the use of digital IDs.
Delta Mail features support for multiple e-mail accounts, file attachments and printing, an address book and account manager, the ability to queue e-mails in an outbox, remove message indentation, search for e-mails, display messages in any font and view/download/delete e-mails on the server.