Unfortunately, Stack Overflow is not a place for every possible programming question on the planet. We have a very narrow focus aimed at specific programming problems that can be answered without wild speculation. (For a complete list of what you can ask and what you can't, you should review the Help Center).
While it does seem to meet one of the criteria in the on-topic list, "practical, answerable problems that are unique to software development", the answerable part is the tough one because it isn't truly answerable except by someone involved in setting the standards.
Additionally, what makes it off topic is something from the "what you can't ask" list.
You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page.
Here, "answerable" means the same as above, plus it isn't really a question about a problem you are facing. You actually appear to be asking asking about a specific solution that you think answers a problem you are facing. That is a common problem in many SO questions.
So one way to make this question on-topic is to flip it around. Don't ask about
biginteger and when it will be released, but rather ask the question about what drove you to seek out
biginteger as the solution. You might find a better workaround or even a better solution in a different direction than the one you are currently using. And as a plus, if
biginteger is on the C++ radar, a response about it might actually be an acceptable answer as well.
Another alternative is Stack Overflow Chat. Topics there are a little more open-ended and can be on-topic for more speculative questions, so you might be able to get a response to your