EDAS keeps versions of the review and final manuscripts for about 6 months. They are accessible via the small history (reverse clock)  icon next to the file modification date. This also allows recovering files that were accidentally deleted. Older versions of review papers have been kept for a few months; final papers are versioned as of today. (Versions of other manuscript-related files, such as extended abstract, are not kept.) The versions are accessible to the author and chairs.