Don't worry, it's simple. Just add three records to the DNS for each domain that sends mail out through MailRoute:
mr01._domainkey.<domain>. CNAME mr01.dkim.mailroute.net.
mr02._domainkey.<domain>. CNAME mr02.dkim.mailroute.net.
mr03._domainkey.<domain>. CNAME mr03.dkim.mailroute.net.
That's it! Just substitute your own domain name where it says "<domain>" of course. Once those records are in place, recipients can validate the email that you're relaying through MailRoute, which will increase your deliverability, and generally make the world a better place.
For GoDaddy DNS instructions please see here
If you already have other DKIM records from us, those will continue to be supported at least through the end of 2021. But we urge you to add these records as well, so that the transition to the new signing system will be transparent to you, and we can start using our advanced automated DKIM key management systems to your full benefit.
What??!? Why aren't you? The service is included with your inbound filtering service, and using our Outbound/SmartHost relay service will not only increase the deliverability of your email, but it helps us better filter your inbound mail, and reduce any potential false positives. We can use info about who you correspond with to adjust the scores of messages from those people. It's sort of like a "soft allow-list" that we can dynamically adjust to give you the lowest false-positive rates and best email filtering possible.
All you need to do is add your servers to the "Outbound Servers" tab in our Control Panel at http://admin.mailroute.net. And then set your mailserver up to relay outbound mail through MailRoute. We have a whole set of articles about this on our KB at https://support.mailroute.net/hc/en-us/sections/205311868-Configuring-Outbound-Service
Here's our KB article about properly setting up your DKIM records that gives more detail on setting this up, if you need it:
We've got new articles on our KB about this stuff, about email Authentication in general, DMARC, and SPF. Check them out: