D7 is supported for production at least thru its d.o EOL in November 2021.
D9 is scheduled for a forced release in June 2020 due to Symfony mandate, upon its release it will replace D8 here, and the migration of curated D7 modules will begin in earnest. Until then, D8 is supported for development of the dual version feature and to support clients that may have committed to it on a custom consult basis.
See first footer link for the underlying software packages.
Login here is for admin/operator use.