GitHub announced upgrades to its network infrastructure, necessitating the decommissioning of outdated equipment and the cessation of HTTP, Git, and SSH requests to old IP addresses not returned from DNS for several domains, including github.com and api.github.com, effective November 5, 2013. Users are advised to remove any related entries in their /etc/hosts file or equivalent configuration files on Windows to avoid disruptions in service. The DNS servers are set to return the IP address of a random, healthy load balancer for these domains, and users are discouraged from replacing old entries with new ones, but rather removing them to ensure continued functionality. Jesse Newland emphasizes the importance of checking and updating network settings, especially for users experiencing warnings on GitHub.com, to facilitate a smooth transition to the updated infrastructure.