Fans of Ubisoft multiplayer titles will be pleased to know that they will be migrating from a third-party data center to servers in a new facility. What they may find inconvenient is that some games will be unavailable while the transition is taking place. On February 7th at 8PM EST, services for some PC and MAC based online play will down. Uplay will be completely down, however, they are posting progress updates on their Twitter account. They list all effected and unaffected games here.
Source: Ubisoft