From a post by Scrivener tech support:
Reference:
[url]About Scrivener 3 price and upgrades - #7 by kewms]
Scrivener 3.0 for Mac was released on 20 November 2017.
Reference:
[url]Scrivener 3 for macOS Release Date]
Therefore the cutoff date is 20 November 2017.
Hope this helps!