For certain countries (e.g. China), AHAspeed app is not available in app store. But you can still install AHAspeed iOS app as custom enterprise app.
Step 1 - Manually install AHAspeed iOS app
When you first open an enterprise app that you've manually installed, you see a notification that the developer of the app isn't trusted on your device. You can dismiss this message, but then you can't open the app.
Step 2 - Go to "VPN & Device Management" Settings
After you dismiss this message, you can establish trust for the app developer. Tap Settings > General > VPN & Device Management. Under the "Enterprise App" heading, you see a profile for the developer.
Step 3 - Tap "Enterprise App" section
Locate the "Enterprise App" section of the "VPN & Device Management" page, tap it to enter to next page.
Tap the name of the developer profile under the Enterprise App heading to establish trust for this developer.
Step 4 - Trust the developer
Tap the name of the developer profile under the Enterprise App heading to establish trust for this developer. Then you see a prompt to confirm your choice.
Step 5 - Open the app and allow "Add VPN Configurations"
Reopen the app, then you will see a "Add VPN Configurations" prompt. Click on allow. Without allowing, the app will not work.
The end
Learn more about installing custom enterprise app on your iPhone & iPad: https://support.apple.com/en-us/HT204460