You might be disappointed if you were planning an Ubisoft-themed nostalgic gaming session. Kotaku reports Ubisoft has shut down online services for 91 games. Many of them are ancient, or versions for old (and sometimes defunct) platforms. You aren't about to play Assassin's Creed: Brotherhood using the long-dead OnLive service, for instance. However, there are some games you could still play on current hardware, or might have good reason to revisit.
The first two Far Cry games have lost online support for PC, for instance, and Blood Dragon won't connect on PC, PS3 and Xbox 360. Just Dance fans may need to stick to newer games. While it isn't surprising that Ubisoft dropped support for PS3, Wii, Wii U and Xbox 360 versions of Just Dance 2018 and before, PS4 and Xbox One players might not enjoy losing access to the songs from Just Dance 2014 or 2015.
Other classics you might miss include Beyond Good & Evil, the original Ghost Recon, multiple Rainbow Six games, older Settlers titles and certain Splinter Cell releases (including Chaos Theory and Conviction). Games that used Ubisoft Connect won't let you earn Units, and you can't unlock content on any platform or access it on PCs.
Ubisoft isn't exactly rushing to leave some players in the dark — it's just now shutting off Rainbow Six Lockdown support for PS2, GameCube and original Xbox owners. All the same, you probably won't be thrilled if you've kept an old console around to play the games of your youth.