If you use a standard distribution like Slackware, Debian or Redhat there probably is no need to upgrade. Installing sysvinit is only for those that upgrade their system by hand or for people that create Linux distributions. Sysvinit is probably the most widely used init package for Linux.
Most distributions use it.
Sysvinit is now a debian package. Unfortunately I was not able to fix this at the time because I was abroad for some time. Wrt 2.4, some of the code has been made simpler. This can be configured with an access file.