Your final executable is locked for modification until the end of the judging deadline. Of course, there is nothing stopping you from continuing to improve your game/source on your own and even work on a post-jam version of the game to upload after the judging period is closed. If you do end up doing this, I would recommend creating a Tag in your source control to tag the point of submission for your game so that people can review the source at that point if they so choose.
