In a nutshell from some random article I ran across:
Final Fantasy XIV players, take note: Your days are numbered. Er, at least your days spent in the original FFXIV world. When the game's rebirth, called A Realm Reborn, occurs later this year, the game's servers will be taken offline. Rather than overlap the two versions of the game, Square-Enix director/producer Naoki Yoshida says the original servers will be taken offline "some day in the near future," precipitating an alpha and then a beta for the game's relaunch later this year.
"Basically what's going to happen is that the current story is still continuing now, but some day in the near future -- and we'll make sure we tell the players what day that is -- something is going to happen in the story, and at that time, the servers are going to shut down," Yoshida told us in a group interview this morning at Gamescom.
The reason for the shutdown is less thrilling than you might think. "Basically the player data will be taken over into the new game. So, to convert all this new data for the new systems, we need a certain amount of time to do this. There's so much data, so many thousands of characters that we must do this for. And so we have to shut down the servers," he said.
Yoshida was quick to point out that players will have plenty of warning ahead of the shut-down (consider this your first heads-up). He also notes that the original game's userbase will be prioritized in A Realm Reborn's beta queue and that players will "be able to use their current characters in the beta test as well." Though that may not be at the kickoff of the beta, he says, "We're working in a way to try to get it as close to the beginning of the beta test as possible."
Alpha + Beta testing on something that cannot fail...we are talking months of server shut down while testing occurs. I would assume we will be playing 2.0 sometime early 2013...but how early...who knows. Depends on when they shut it down.