This is an old revision of the document!
Current devel version will be numbered 5.3.0 and it is planned to be released in the autum 2019.
Its features are documented here: https://www.kamailio.org/wiki/features/new-in-5.3.x
Previous devel, current stable, version was 5.3.x (released on October, 2019), see what was new in that release at:
This is a draft of new features added in devel version, manually updated, thus not always synchronized with what is new in source code repository.