libnet-server-mail-perl 0.23-1ubuntu1 (arm64 binary) in ubuntu bionic

 Net::Server::Mail is a versatile and extensible implementation of the SMTP
 protocol and closely-related protocols like ESMTP and LMTP. The event driven
 object-oriented API makes it easy to incorporate the SMTP protocol into perl
 programs.
 .
 It provides a mechanism to easily add future or not yet implemented ESMTP
 extensions. Developers can hook code at each SMTP session state and change
 the module's behaviors by registering event call-backs. The class is designed
 to be easily inherited from.