Very quietly and without warning, Assassin's Creed: 4 Black Flag was recently removed from sale on Steam. It's still listed, and you can still access it if you already own it, but new purchases aren't currently possible. The surprise shutdown sparked hope among some fans that Ubisoft might be working on a Black Flag remake—and maybe even that a surprise release could be in the offing. But Ubisoft says that's not actually the case, and that sales of Black Flag weren't intentionally halted. Something's just gone wrong.
"We are aware that Assassin’s Creed Black Flag is currently unavailable for purchase on Steam," a Ubisoft representative told PC Gamer. "This is due to a technical issue, and our teams are working on a solution to bring it back as soon as possible."
Assassin's Creed 4: Black Flag is easily one of the best in the long-running series—we called it "a gorgeous, relentlessly entertaining open-world piracy simulator packed with interesting 18th century rogues" in our 90% review—and so it's understandable why people would want a remake. As good as it is, it's also 10 years old now, and in videogame terms especially, that's an awful lot of time passed.
That hope was bolstered by a Kotaku report in June saying that a remake of Black Flag is already underway at Ubisoft, although if so it was (and presumably still is) very early in development. Incredibly, Ubisoft is also still working on the eternally-delayed (and, frankly, not very impressive-looking) multiplayer piracy game Skull and Bones, which was originally envisioned as a spinoff of Black Flag's ship-to-ship battle bits.
It may yet happen, and it'd be great if it did—but, I'm sorry to say, the current Black Flag situation on Steam is not a sign that a big announcement is imminent.