This first alpha includes three major changes compared to : exmpp library is used, gen_storage for a database abstraction layer, and Massive Hosting which isn't yet usable.
Many tables have changed both in Mnesia and MySQL/PgSQL/ODBC. Fortunately, now ejabberd is able to create tables, update the tables and reformat their content in Mnesia and also in external databases. Or at least it should do.