Requirements for Test Flight
iOS
Minimum OS version requirement: iOS 11.0
This means the following devices whose maximum OS versions < 11.0 are NOT supported:
iPads: Original iPad, iPad 2, iPad 3rd Gen, iPad 4th Gen, iPad mini 1
iPhones: prior to iPhone 5S
Installation steps
Install TestFlight from App Store on your iOS device
Accept the invitation.
Check your mailbox for TestFlight invitation mail. Its subject should be "Bugo, LLC has invited you to test...".
Note: You must use an Apple account's email in order to join the TestFlight test.
The latest beta version of the Mail Center app should appear in your TestFlight app.
Tap on the app's name to view its information
Select "App Details" for more information, including compatibility (required OS version, supported devices)
Select "Previous Builds" to install a legacy beta build (if any).
Android
Minimum OS version requirement: Android 6.0 (named Marshmallow, API level 23)
There are more than 6000 supported devices, so we won't list them here.
Installation steps
Visit the opt-in URL to join the beta program:
Note: You must log in with your Google Play Store account, which is the same as the email that registered to be testers of Anytime Mailbox, or else you cannot either join the program or install the beta versions.
Open the Play Store on your device and install the app normally.
Note: For beta testers, you may have to wait for several hours or days before a new beta version is available in your Play Store. An internal test should be available immediately after publishing though.