We've added some new mail servers into our SMTP cluster to increase capacity.  This has required us to change the IP address of the SMTP cluster.  We'll be updating our DNS later on this evening to switch everyone over automatically to the new cluster.

Any resellers that have created custom DNS entries pointing directly at the old IP address (217.154.106.23) will need to update these to point to the new (217.154.106.151) address.  We'll be monitoring the users of the old cluster IP address for several days to ensure it is unused before retiring.