Yes, it should be early next year as sejgiul said. Unfortunately the way these OTA updates work, it's the carriers/networks that deliver the update to their own network. They like to test it thoroughly before releasing it. This is why some networks pushed down the updates to their phones, weeks or even sometimes months ahead of others. It can be very frustrating, when people are getting the updates at different times. I'm on the EE network and we had to wait longer than most other networks here in the UK to receive the Amber update. Some networks such as AT&T in the US were made to wait much longer than this.
With the last update which was Amber, Nokia had a page on their website, which showed the status of the update for different phones and networks. You can see this page
here. I would think they will do the same thing with the Black update.