The upcoming Postmark iOS app is designed as a troubleshooting tool to help users quickly debug and resolve email issues on-the-go. The app offers features such as message search, inspection, bounce investigation, server stats monitoring, and account management. It aims to provide an optimized mobile experience for customers who need these tools, building upon the desktop version's success. Secure access is ensured through Touch ID or Face ID. The beta program allows Postmark users with admin or owner permissions to test the app and provide feedback.