Community Builder can be freely downloaded by all registered members
We just released Community Builder 2.1.6 that addresses some regressions from the Community Builder 2.1.5 Security and Maintenance Release.
CB 2.1.6 is a simple one click upgrade for all CB 2.0+ websites (as always you should first take backup and test your upgrade on a cloned site) and is a highly recommended update for all Community Builder websites.