It is 1 house per account per server.

This means you cannot have 2 private houses on the same server, unless of course you had them prior to the change. This is how some players can, and other players cannot.

You can have 1 private house and 1 free company house on the same server.

You can have 1 private house, and 1 free company house on different servers on the same data center.

You can have as many apartments as you have leveled characters.

You can even buy and sell or "occupy" as many free company houses as you like. There is a simple work around for the "1 FC house per account per server." Which many bots and such use to continue to exploit the housing system utilize.