CentOS Linux 7 ?
• possible to keep ? / through 2024 ?
CentOS Linux 8 ?
• upgrade optional ? / to the end of 2021 ?
CentOS Stream ?
• upgrade mandarory ? / when ?
CentOS fork ?
• which one ? / when ?
CentOS 7 will be available through 2024.
We don't currently support CentOS 8. Since they recently announced the changes you mention (CentOS Stream, multiple forks) we stopped working on the CentOS 8 version of the platform. Once everything gets figured out in the next few months I'll evaluate it again.
Thanks, keep in touch & stay covid-19 safe!