A supported Java version is required. Check the release notes for latest supported version.
If Java is not installed, a prompt is displayed that the file cannot be opened, with an option to search for the program.
VKCS Launching:
For all browsers, the VKCS standalone application needs to be downloaded everytime you use it.
Chrome: The downloaded VKCS jnlp file must always be clicked at bottom left corner of browser window to launch.
Edge: You can allow and open the file from the browser downloads in the top right corner.
Safari: Save the jnlp file locally. Hold down the Ctrl key when selecting to open, then click Open in displayed prompt
Firefox: The current default setting in Firefox on Windows saves the file and runs from the download. You can launch from the browser with this setting: Tools>Options>Applications, then select "Jnlp File" in the Content Type column, and change the Action from "Always ask" to "Use Java Web Launcher".