The final version of your paper will be made available to conference attendees. This version should incorporate all feedback from the conference reviewers. This is the version of your paper that attendees will review prior to your presentation, and attendees will ask questions based on this paper, your presentation, or both. For this reason it is best that your presentation be based on this version of your paper.
The exact format of this version of your paper is up to you. While the version of your paper that you submit for publication must be in a specific format, that is not the case for this version. However, if you are planning to submit your paper for the proceedings, having it in that final format will both be easier for you to maintain up to the camera-ready deadline, and it will be easiest for proceedings editors to determine that it is, indeed, the same paper that was presented.
The deadline for this version of your paper is given on the Instructions for Authors page for the conference. Also shown there are details on the format for the proceedings and the deadline to ensure publication in the proceedings.