I really wish there was an updated one somewhere, but as far as I am aware the HMRC won't change until the new tax year as it only works out what you get this year, so if you're income is less than £32,000 you should be entitled with 2 kids before April then I guess it's seeing what happens April 6th when you can use the updated calculator.
I really wish I could get some information about the changes, the unison one only goes up to £38,000 but we earn more than that (the childcare element is higher than the standard allowance) so I'm assuming the whole calculator is disregarding what element of TC you are entitled to. I really wish HMRC would publish something as simple as that!