Our iOS app uses UDP packets to get a status update from one of our Internet servers. This has been working fine for the last couple of years. The app uses the BSD socket interface with C++. During review last week our app failed to get any answer from our servers. After a couple of changes we added a backup mode where the app will retrieve the same status by using a TCP connection when UDP fails to get a reply. This worked fine and the app went trough review and is now in the store. On our server I can see status requests from users who have installed the app on their devices, and these never fall back to TCP, the UDP just always works. Is there a particular reason that UDP traffic is blocked on the network used for reviewing?