How to solve ''Failed to open map file, saved with a newer version'' problem?

Hi, Im saving my folder and autosaves are work all the day but while I saving the project, it crashed and now I got this error message. I do not know how to open it because in my content and saved folder, 4 of my autosave.umap files are from 1 month before. If I can not solve it, I have to go back for 1 month. Can anybody help pls?