The recommended way of safely upgrading Ruby implies that you have installed your Redmine server's Ruby using RVM (Ruby Version Manager). RVM works under both Linux and Windows. This recipe deals with a scenario where you want to upgrade the Ruby version on which your Redmine instance is running.
Make sure that you have server administration privileges.
Check the requirements of the Redmine version against the Ruby version on Redmine's website installation instructions, at the following URL: http://www.redmine.org/projects/redmine/wiki/RedmineInstall#Requirements.
Assuming that Ruby on your server is installed with RVM, upgrading Ruby should be very easy and straightforward. RVM even lets you use multiple ...