I don't think it's an unreasonable question. If it might take awhile, they are better off just saying that. You leave people to wonder and they just go away thinking the worse. This is not a no news is good news type of problem.
If they don't hit the deadline I am sure they will come forward and give details. I would rather the dev team take their time. A week now saves months of troubleshooting later for hundreds to thousands of people.