In the first message it says:
ACTION REQUIRED: if you are using IPN (Instant Payment Notification) for Order Management and your IPN listener script is behind a firewall that uses ACL (Access Control List) rules which restrict outbound traffic to a limited number of IP addresses, then you may need to do one of the following:.... 
then:
ACTION REQUIRED: if you are using ACL (access control list) on your firewall to restrict outbound access to the IP addresses currently in the DNS when connecting to PayPal API endpoints, then you will need to update your firewall rules to allow outbound access to the additional IP addresses.
basically this means that if the servers firewall has an Access Control List to restrict inbound traffic, you will need to take action and update the ACL list to include the new IP addresses.
This is a server configuration issue, so you will not need to do anything on your part, but your host may need to update the ACL list on the firewall.
The second link is a notice of downtime for the Payflow Pro System.
the third link is a duplicate of the first.
