I'm in the same boat. Here's what I've found out:
These certificates are used by the "Apple Push Notification Service" (APNS) and apparently have nothing to do with Cisco's Access Point Security Protocol (APSP). Push Notifications are used to do things like immediately alert you of new mail on your iPhone (rather than have the iPhone polling every few minutes to check if there is new mail).
Now, how to renew them (in theory because it doesn't work for me - it might for you):
1) open the "Server" application
2) in the Hardware section (top left), click your server
3) click the "Settings" tab
4) presumably "Enable Apple push notifications" is already checked. (if not, delete or move the expiring certificates out of /etc/certificates and that should stop the alert emails)
5) click the "Edit" button after "Enable Apple push notifications"
6) a drop down panel will show the apple ID and expiry for your Apple Push Notification Service certificate. The expiry will probably be in red. Click the Renew button.
7) enter the password for your Apple ID and click Renew certificate.
Hopefully that works for you. I end up with a "An unexpected error (-1) has occurred". If I click on the "Manage your certificates" link, I'm directed to an apple site that has a certificate expiry about 8 months after the one in the Settings page. I'm guessing that's the one being used and not the one shown in my settings page. I'll wait until after the certificates expire, see if anything breaks then delete the expired certificates.
If anyone knows how to determine which APSP:<uuid> certificate is being used on OSX Server or how the Apple Push Notification picks which certificate to use, please let me know. I have five APSP certificates in /etc/certificates and I suspect only one is needed.
Cheers,
Dean