Stop testing a build

Required role: Account Holder, Admin, or App Manager. View role permissions.

From Apps, select your app.
Click the TestFlight tab.
In the sidebar, below Builds, click the platform.
In the table on the right, in the Build column, click the app icon or build string for the build you want to expire.
Click Expire Build.

Internal testers and external testers will no longer be able to install this build.