Expiration certificate iPhone "in house" enterprise deployment

Let's admit that I deployed an app on 100 iPhones, using the apple "in-house" deployment of the enterprise program. All of them will be connected to the internet. What will happen at the expiration of the distribution certificate ? All my employee will need to download the app again, signed with the new certificate ? Or renewing开发者_StackOverflow the certificate will simply allow users to continue using it without downloading it again ?

Thank you very much for your answer...

As documented in Distributing Enterprise Apps for iOS 4 Devices the App will refuse to work if the certificate expires. You'll need to rebuild your app with new certificate and re-distribute, e.g. "over the air".