Today I checked in new changes regarding server-to-server and external components support that require to create 2 new tables in the database. If you install the latest nightly build and forgot to run the update-db-script the server will still run though you will get some exceptions in the error.log. In order to create the new tables run the proper update script located in src\database\upgrade\2.1_to_2.2.
For your information, server-to-server and external components support is almost finished. Latest added features are white&black lists, killing of idle sessions, new admin pages, new pages that show the list of connected components and remote servers, and many improvements/bug fixes.
As you can see this post is a question so for those of you that report any error regarding s2s or external components support, you will get some points.