GitHub introduced updates to its messaging and notification systems, including the addition of a Notification Center in account settings for managing email preferences. New features include default email notifications for comments on commits where a user is an author or committer, and the ability to turn off notifications for specific commits. The email subject lines have been improved for clarity and threading, and pull requests and issue comments have been categorized as notifications rather than messages, simplifying the user's inbox. A "mark all as read" feature has been added to both inbox and notification sections, and the update acknowledges the continued potential for improvements. The development process was facilitated by MockSMTP, a tool for locally testing app-generated emails.