It includes better support for the latest authentication standards (DKIM/DMARC alignment) which are now mandatory for reaching Gmail and Yahoo inboxes reliably.
<domain hotmail.com> vmta hotmail-vmta max-smtp-out 5 use-starttls yes require-tls no helo-host mx.hotmail.com </domain> powermta 60r3
<virtual-mta ipv4_only> bind-ip 203.0.113.5 only # 'only' flag forces IPv4 </virtual-mta> It includes better support for the latest authentication
While version 6.0 was a major milestone, the update specifically addressed: the update specifically addressed: