You have to pony up the money once again to purchase an XT2 with 2 way audio. It is not free. So now you spent somewhere between 150-200 bucks per camera to get this 2 way audio feature. For that price, you could have had it via the competition.
Sadly, that 2 way audio does not work currently worth a damn. Audio lag, low speaker volume are complaints by many people via Facebook, this Community, and Amazon. Don’t get blinded buy your love for a brand and miss out on what reality is. But hey, it’s your money, if you want to blow it, that’s your choice.
Remember I am a customer, not an employee, not a super user, not a beta tester. If you do a good job I will praise it. If you screw up, I will chastise it. Social media will make your company die or fly. That choice is yours if you are a business owner/employee.