This means that if you are so inclined, you can go ahead and download the camera’s firmware via Fujifilm’s website. Instructions on how to update your camera with the latest firmware can also be found on Fujifilm’s website, so if you are unclear about the steps, then just head on over to the website for the details.
For those unfamiliar with the latest update, basically this is supposed to be the same update as version 4.20. However there was a bug with v4.20 that according to Fujifilm, on rare instances, it would cause the camera to freeze up while shooting in AF-C mode. While it was rare, good on Fujifilm for pulling it all the same.
So basically v4.30 is the same update, except with the fixes that should not freeze your camera, so if you are still running on v4.20, then perhaps it might be a good idea to update, or update anyway since updates are usually a good thing.