Rather than being kicked back to the last checkpoint should their connection drop out--as was originally the case--players will be able to resume the game "from the exact same point" when they reconnect. The 19MB patch is over on FileShack now.
Meanwhile, a cracking group claims to have successfully circumvented the DRM solution's implementation in Silent Hunter 5, enabling Ubisoft Romania's submarine sim to run irrespective of the player's online status--or the legitimacy of their copy.
Ubisoft has responded on Twitter saying "any gamer who downloads and plays a cracked version of [AC2] and [SH5] will find that their version is not complete"--a statement that seemingly confirms the crack is functional in some manner.
While Ubisoft does not specify in which way cracked copies are "not complete," it's a safe bet that online saved game storage is one such unavailable feature.