Sophos will be changing the external IP of the PureMessage Unix Repository on September 2020 (exact date will be announced when available).
New IP addresses of the following servers will change according to the following:
Customers who limit access via IP will need to update their firewall rules in order to allow data updates to occur.
Customers using hostnames in their proxy and or firewall will not be impacted.
Operators of Sophos UTMs that use a DNS-Host object for identification, will need to change that to a DNS-Group object
Related KBA: https://community.sophos.com/kb/en-us/135748
Similar IP changes are also being made to the following products: