This is an old revision of the document!
The page contains the details about the changes that were made to old components during the development of v4.2.0 compared with what existed in v4.1.x. It does not include the brand new modules, focusing on how to upgrade database and configuration file from v4.1.x to run with Kamailio devel.
If you look for the guidelines to upgrade to previous stable release, see:
Changes to default values: