The 2021 Casper workshop will be held online Monday-Thursday during one week in May. Please vote on the dates below by selecting all the weeks that work for you. To maximize the anticipated participation, we plan to schedule sessions during morning hours in California, which are late-afternoon and evening hours in South Africa. If there is sufficient interest from other time zones we may add a session at a different time. All talks will be recorded and posted on the conference website, to be available to those who can't attend the live sessions.