We support 2 versions for CentOS.
For example, if CentOS project supports CentOS 5, 6 and 7. We will drop CentOS 5 support and support CentOS 6 and 7.
We support stable, testing and unstable.
We don't support oldstable.
We will release package once for oldstable when Debian project release new stable. And we will announce that we drop oldstable support.