From Software disabled the servers for Bloodborne's online service just a week after The Old Hunters was launched. They provided zero explanation for why they did so, but there is speculation that a loophole in the system allowed players who didn't own the expansion to play it for free.
Here's what the game's lead hosting engineer Tim Wernicke had to say about the issue on reddit:
“Thanks to the community here, we’ve received some really important feedback about an exploit and serious issues that exist in the game. The game is currently undergoing emergency maintenance, and we’re working non-stop to get some things patched and back online. So a huge thank-you to everyone here for the feedback, and please be patient while we work to get things restored.
I apologize that I can’t be more specific, but I wanted to let you know that we value your feedback, and what you’re doing here is really helping. So, thanks!”
According to people who accidentally (or knowingly) exploited the loophole, simply joining the game of someone who owned The Old Hunters would allow them to access its content for free even after disconnecting.
The servers are back up now with the code fixed.
