As far as I know, downloads for 4.18 or 4.30 Vue firmware have never been publicly released by Davis. I don't know why - there is no obvious reason for them not to be available, other than the need to check that the Vue console is MB revision or later. But TBH there are only minimal differences between 3.00 and 4.xx - I doubt that you would notice any practical difference at all.
But the bottom line is that you should contact Davis support by email, quote your Mfg Code and ask them directly for a copy.