File type for custom scenarios - 'Invalid file'

So I downloaded some custom scenarios and campaigns, but majority of them are giving me 'Invalid file' when I try to run them. Minority of them are runnig, problem is in those file types.

When those files are of .age3scn file type, they won't run, they need to be .age3yscn instead.

So my question is, if anyone encountered same problem, is it safe to change file type to .age3yscn and they will run properly?

I am on DE.