I'm using the Modern theme since day 1 i installed Osclass (14 months ago). I have heavily modified it and still enjoy it.
Recently after the image drap and drop upload change, i was doing some cleaning. So i got the full theme from Github and compared each and every file in there with mine.
I was surprised to see that more than 12 php files were different than mine. It seems that during those 14 months the theme was updated but for some reason mine was not.
So if you run the old Modern theme, compare your files against those of Github.
You can do the compare (and the merge if you like) with Code Compare Free Version.