There's no need to update your firmware if you've already got it installed already. But how do you know?
For all Vesper Marine products, you can use the vmAIS utility and it will tell you the current version. Please be sure to download and install the latest version of vmAIS from http://www.vespermarine.com/support/downloads/
When you connect to your device via USB, serial or WiFi you'll see one or two version numbers in the box at the top of the screen. For XB-8000 and Vision both versions will be included. For other products, there will be just the AIS Version.
If both of these versions match, then there is no reason to do the update.... you've already got it!