3.1 r4 发布了，何时会有 CD 镜像下载？

[liushk]

http://www.debian.org/releases/

The current "stable" distribution of Debian GNU/Linux is version
3.1r4, codenamed sarge. It was released on October 28th, 2006.


另外，如何判断当前的 Debian 系统是 r3 还是 r4？
还是只要 apt-get update、apt-get upgrade 后自动就升级为 r4 了？