First, make sure 5UF VPN is updated to the latest build from the App Store. Version 9.3 for iOS ships a new core engine with better stability and performance, and fixes most issues where the app could not run properly on iOS 16 and similar versions. If your device runs iOS 16 or later, update the app to 9.3 or newer and try again.
Release notes (Chinese page): 5UF VPN iOS 9.3 announcement.
If you are still on iOS 15 or earlier, or your device cannot upgrade to iOS 16+, the official app may remain limited on very old systems. Options:
- Upgrade iOS as far as your hardware allows, then install or update the official app; or
- Use a third-party VPN client with 5UF where appropriate.
Tutorial: How to use a third-party app with 5UF VPN
If problems continue after updating, contact support with your iOS version and app version so we can troubleshoot.
