In order to improve security, Takumeadome [Mailad Poipoi] uses conventional client-server encryption (HTTPS), as well as
Communication between servers also supports encryption (STARTTLS/SMTPS).
Encryption for transmission between servers requires that the other party (the sender for receiving, the receiver for sending) support the same.
As shown below, there are no services that support this in Japan.
For example, all emails between Gmail and your abandoned email address are sent and received in a secure manner.
https://www.google.com/transparencyreport/saferemail/?hl=en#region=142 Note that this function does not require any settings on the user side.
