Apply Rails security patch on production system

My customer's site is running following versions $ rails -v Rails 2.3.5 $ ruby -v ruby 1.8.6 (2010-02-05 patchlevel 399) [x86_64-linux] This project consists of following steps 1. backup current version 2. applying the security patches referenced on [login to view URL] 3. in case it fails solve the problems This site is in production but there is no problem that is down for 1 hour or so.