WOW, your level of misinformation is astounding.
The publisher/developer are responsible for updates.
Years ago, some publishers left digital versions out of date and just updated their retail disc versions.
Since the retail market has died, digital versions now get updated as and when needed.
All Cliffs of Dover versions run through Steam therefore all versions are the same.
The latest unofficial beta is not on Steam but that is because it is unofficial and the publisher will not authorise the update.