Sale date announcements since 2009.
2009: 30th July
2010: 17th September
2011: 1st September
2013: 20th June
2014: 16th September
2015: 15th September
2016: 18th September
2017: 12th September
2019: 17th September
2020: 17th September
2021: 25 August (confirmed no October sale)
2022: 21 January (when 21 fest cancelled, FAQ included note that resale for 2022 would be April 22)
2023: 23rd September