The main server keeps one complete copy of translations plus the differences between that copy and one previous copy. Each copy has an associated day and time (timestamp). If the translation timestamp of the survivable core server matches the timestamp of the main server’s current translations, no translation download occurs. If the timestamp of the survivable core server matches the timestamp of the main server’s previous copy, the main server sends only the differences to the survivable core server. If the timestamp of the survivable core server does not match either of the main server’s copies, then the main server sends the entire translation download to the survivable core server.