Hmm, you were indeed not clear
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
In every version of the game you must use the savegames from the same version as provided by the developer. With that you can use Autosaves to go back to earlier versions. If you did that, you can ignore the warning
I also have a strong suspicion that some people start a new game in v027 but copied the savegames from an earlier version. You think that with a new game those would be ignored, but if a bookmark01.dat is present that would be used instead of an internal version. So then you're screwed as well