The document could not be opened

I just updated the app to 2.5 and now I get the message that I can’t open a file I was working in few days ago. It tells me that I can try fixing the file in Text editor, but that doesn’t really help since I don’t know what’s wrong.

Can you send me the file?

On further inspection, I saw that the file was less than half the size it should be compared to earlier versions. Something must have gone wrong when I saved the file when I was updating(the file from few days ago was still open). But I managed to restore the file from Dropbox, so all good now!