For details of what is included in this version, please refer to the change log.
The installation package can be installed directly from within Visual Studio (through the ‘Tools > Extensions and Updates...’ menu). Alternatively, it can be downloaded from this page.
Contrary to what was mentioned in a previous post, the new QML debugging feature will not be enabled by default. It must be explicitly enabled by opening the Qt project settings and setting the "QML Debug" option to "Enabled".