Current devel version will be numbered 5.3.0 and it is planned to be released in the autum 2019.

Previous devel, current stable, version was 5.3.x (released on October, 2019), see what was new in that release at:

• http://www.kamailio.org/wiki/features/new-in-5.3.x

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.

Manage headers using $xavp to keep the desired final value.

• https://www.kamailio.org/docs/modules/devel/modules/pv_headers.html