How to upgrade Ruby to version 1.9.2

Hello,

We followed the procedure here http://www.interworx.com/support/faq...and-passenger/ to install Ruby.
Now we have ruby 1.8.7 (2011-06-30 patchlevel 352) [x86_64-linux] installed successfully.

But the package we want to run asks for version 1.9.2, how can we upgrade to Ruby 1.9.2 without breaking anything?

Thanks,

Rodrigo