As we are about to log in, we receive the message that Modern Warfare is offline due to server maintenance.
At the moment it is not possible to play Modern Warfare, all platforms are offline.
How long the maintenance will last, was not mentioned. Whether it is a preparation for Announced Modern Warfare Update 1.07 has not yet been confirmed. The only message Activision has released so far:
12:08 PM PST We're currently experiencing connectivity issues. This incident is under investigation.