If you are talking about the game page, yes you can. It is considered a separate project that has been submitted to the jam actually. Or so I think. I hope I am not telling you bullshit...
According to the mail from Sunday: "Also: you may change your itch.io page after the jam is over. You may also upload a new build if you want, but keep the original jam build that you made in the 48 hour time slot, and clearly label it as such, so people know which version to actually judge!"
