We have deprecated our Asset Store package for Vivox and moved to be more tightly incorporated within the Unity Gaming Services. Vivox is still a living and growing product and the deprecation of our Asset Store Package does not mean we will stop offering providing access and updates to Vivox Service.
Vivox will continue to be accessible through the Unity Package Manager in the Unity Editor, and most recent and future versions of Vivox will continue to be posted on there.
To learn how to access Vivox through our package manager, please see our Vivox: How do I get started with Vivox in my Unity Project? KB.