The Postmark Slack App is now live, allowing users to receive bounce notifications and interact with the app through a slash command. The app provides a direct link to Message Details pages for investigation, and can be installed in any Slack channel with a few simple steps. Users can currently only specify one bounce webhook URL per Postmark server, but this limitation will be addressed in future updates. The app has big plans for expansion, including displaying recent stats and activity, and the team is seeking feedback from users to determine what additional features should be added.