We regularly release new builds to our Beta Testers via TestFlight, but it may be that every now and then a build expires or simply becomes unavailable.
If that happens (for various reasons), we usually replace it with a new one within a few hours, and you'll get a notification to install it again.
Don't worry, your in-game progress shouldn't be affected, just install the new build when it becomes available and log in with your existing details to continue building your empire!
Update: we've recently switched over to a new testing environment. If you haven't switched over as per the instructions emailed to you, your build will have now expired! Please follow the instructions in the email(s) we've sent you to get set up.