As is the way with games with online connectivity and multiplayer on dedicated servers, at some point in the distant future, parts of or entire games will no longer be playable. As part of a focus on "newer or more popular titles"
Ubisoft is decommissioning servers for a number of its legacy titles.
With the common outcome being "you will be unable to play multiplayer" and "online features" being removed. On the PC side though, it gets worse as DLC for games like Assassin's Creed 3 and Driver San Francisco will no longer be accessible. And in the case of the online only Space Junkies (a VR title release in 2019 that is still on sale), it will be completely unplayable.
Here's the list, and platforms affected. And with Assassin's Creed, Driver, Far Cry, and other major franchises included, it's a pretty massive change.
Anno 2070 (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Assassin's Creed II (PC, PlayStation 3) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Assassin's Creed 3 (2012 Release) (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features. Additionally, the installation and access to downloadable content (DLC) will be unavailable.
Assassin's Creed 3 (2012 Release) (PlayStation 3, Wii U, Xbox 360) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Assassin's Creed Brotherhood (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features. Additionally, the installation and access to DLC will be unavailable.
Assassin's Creed Brotherhood (PlayStation 3, Xbox 360) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Assassin's Creed Liberation HD (PC) - You will be unable to link Ubisoft accounts in-game or use online features. Additionally, the installation and access to DLC will be unavailable.
Assassin's Creed Revelations (PlayStation 3, Xbox 360) - You will be unable to play multiplayer or use online features.
Driver San Francisco (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features. Additionally, the installation and access to DLC will be unavailable.
Driver San Francisco (PlayStation 3, Xbox 360) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Far Cry 3 (2012 Release) (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features. Additionally, the installation and access to DLC will be unavailable.
Far Cry 3 (2012 Release) (PlayStation 3, Xbox 360) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Ghost Recon Future Soldier (PlayStation 3, Xbox 360) - The multiplayer for the game will be unavailable. To play the solo campaign, you will have to set your console into offline mode.
Prince of Persia: The Forgotten Sands (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features. Additionally, the installation and access to DLC will be unavailable.
Rayman Legends (PlayStation 3, Wii U, Xbox 360) - You will be unable to link Ubisoft accounts in-game or use online features.
Silent Hunter 5 (PC) - You will be unable to link Ubisoft accounts in-game or use online features. Additionally, the installation and access to DLC will be unavailable.
Space Junkies (PC - HTC VIVE, Oculus) - As a multiplayer only title, you will be unable to play the game going forward.
Splinter Cell: Blacklist (PC) - You will be unable to play multiplayer, link Ubisoft accounts in-game or use online features.
Splinter Cell: Blacklist (PlayStation 3, Xbox 360) - You will be unable to link Ubisoft accounts in-game or use online features.
ZombiU (Wii U) - You will be unable to link Ubisoft accounts in-game or use online features.
On the plus side, remastered versions of games like Assassin's Creed 3 and Far Cry 3 will not be affected. Though one has to wonder if a free upgrade should be in order for those affected.