No, you have to remember that Tesla doesn't release updates like Apple. Not everyone gets every update.
In looking at ev-fw I can see that 1,149 cars reported getting a 2017.42.x release. Only 239 reported getting .44, 245 getting .46.x, and 85 getting .48.
So my guess is that more than 50% of the people that got .42 are still on .42.