These enhancements are set to go live on October 1st 2019.
While that may seem like a long way off, there's a task you can carry out now to ensure that the upgrade runs as smoothly as possible and that you don't experience any problems.
What you need to do
If your outgoing server is currently using port 25 or 465, you will need to change the port to 587. We recommend using STARTTLS encryption.
You can keep your server name the same, it's just the port that needs to be updated.
When you need to do it
The sooner the better. These settings will work today. If you leave it until after the go-live date you won't be able to send any emails until you make the change.