Every 2 weeks a new beta is released. We are due for Beta 4 on the 27th of October.
2 weeks after that we will either see a beta 5 or the official release.
Nov 10th could possibly be the day, otherwise it's the 24th.
I *highly* doubt there will be 6 beta versions...5 at the most. If there were 6 beta's, then the official release would likely be on Dec 8th, which is very unlikely.