This is a bug-fix release (with a couple of new features thrown in) that will require the update script to run if upgrading from 2.1.4. See the 2.1.5 Milestones for specific bugs and features.
In addition to the bug fixes and new features, there were some fairly major behind-the-scenes coding efforts going on, most notably the beginning of an internationalization effort toward making BCOE&M easily translated into other languages. This effort will complete in subsequent 2.1.X releases. If you are fluent in English and another language, please contact me if you are willing to help with the translation effort!