If you have an iOS device and you are managed by Microsoft Intune (or Hybrid) you may see an expired certificate in your Management Profile on your device. When I saw this I contacted the Intune PG and they came back that there is nothing to worry about! This certificate is only needed to install the management profile on iOS devices during the enrollment process. After the enrollment is done, this certificate is not used anymore.
So what you will see is that devices that are already are enrolled will work as expected and newly enrolled devices will receive an iOSProfileSigning certificate with the new date.