This release improves the authentication and access control possibilities in two ways. Firstly, all of these options can now be set on a per-listener basis. Secondly, the capabilities for plugins has been extended. It is now possible to define multiple plugins alongside the default security features, and plugins can get access to a wider variety of information about a client to allow them to better determine what authentication/access control requirements apply.
The client library has gained some help functions to allow extremely simple subscribing clients to be constructed. All UTF-8 strings are now validated.
The command line clients gain a few new features, including being able to specify the output printing format and improved TLS error reporting.