Vivox: Why am I getting "IVivox component is not available" when using Vivox and Lobby

Issue:

When using Unity Lobby and Vivox in the Unity Editor the following warning is displayed:

Version define UGS_LOBBY_VIVOX is defined, but the IVivox component is not available.
This means you do not have the Vivox package in your project!

Environment:

Cause:

This warning is the result of having Lobby and Vivox packages installed, but not the version of Vivox with the component that Lobby is looking for. Currently, the version of Vivox with the missing component has yet to be released.

Resolution:

You can ignore this warning. It will be removed in a future Lobby update. The feature will be reenabled once the required version of Vivox has been released.