The page contains the details about the changes that were made to old components during the development of v5.2.0 compared with what existed in v5.1.x. It does not include the brand new modules, focusing on how to upgrade database and configuration file from v5.1.x to run with Kamailio devel.
If you look for the guidelines to upgrade to previous stable release, see:
Following tokens are used to mark the changes:
Run following SQL statements in MySQL client to upgrade database structure from v5.1 to v5.2: