I believe they shut down the servers for the first game only. I still have an old ipad with the game installed on it, and i am still able to connect to their servers. They probably shut the first games servers down because they were releasing their second game at that point.
You can find the zombie farm 1 APK online and use an emulator to run it. The problem is, the game's servers have since been shut down so it is unplayable. However, if someone were to find and publish the zombie farm 2 APK online, we could actually play it.
