By default, Liquid Glass is enabled for apps that are built with Xcode 26. For
any Xcode 26 version, Apple has provided the UIDesignRequiresCompatibility
Info.plist key to opt out of Liquid Glass. However, Info.plist values are
impossible to either partially enable or gradually roll out.
But today someone in a private Slack workspace mentioned there is a
private/Apple-defined User Defaults value that controls whether the app enables
Liquid Glass even with UIDesignRequiresCompatibility in the Info.plist:
com.apple.SwiftUI.IgnoreSolariumOptOut. Set this value to true and
UIDesignRequiresCompatibility is ignored, enabling Liquid Glass; false
re-disables Liquid Glass:
// Enable Liquid Glass
UserDefaults.standard.set(true, forKey: "com.apple.SwiftUI.IgnoreSolariumOptOut")
// Disable Liquid Glass
UserDefaults.standard.set(false, forKey: "com.apple.SwiftUI.IgnoreSolariumOptOut")
This is more dynamically settable than the Info.plist, making it easier to get internal builds tested with and without Liquid Glass or have a more gradual rollout. Note that the app needs to be restarted for the changes to take effect for both enabling and disabling.