Here are descriptions of the more relevant changes in EVSS  16.0

Enterprise Voice Security Suite

End-to-end security in messages

End-to-end security is supported for ZRTP calls. This major version adds end-to-end security also to secure messages.

Every client has an asymmetric keypair used to encrypt/decrypt messages via NaCl box model.  PrivateServer  is the keyserver providing public keys to clients.

Read notification

Users can receive a read-notification, knowing whether and when their secure message has been read. Feature can be enable in application settings or via provisioning profile by system administrator

PrivateWave changes

This version carries a User Interface redesign of clients and server, plus many new devices and OS version support.

PrivateServer changes

OS platform

Version 16.0 brings a brand new core OS platform: legacy OS core based on Fedora Core has been replaced by CentOS 7, with a stable, robust, reliable distribution.

High Availability

PrivateServer  now supports HA cluster in Active/Passive configuration, to gain more reliability and lower downtime due to failures or maintenance.

Activation code

System administrator has a clear view of licenses, including single client and temporary one used to manage transient users.

Web administration console layout has been revised to improve usability, splitting daily maintenance tasks from extraordinary tasks required rarely or during system setup.