In Ruby a lot of us face these types of situations, where upgrading to a newer version could potentially break your code which used to work fine in an older one.
The fantastic Mr. Wayne E. Seguin faced it too, and created a great tool for solving this called rvm.
In a nutshell rvm lets you install different versions of ruby (1.8.7 or 1.9.2 for example) and easily switch between these with a simple
rvm use 1.8.7
You should go to https://rvm.io/ and learn how to install rvm on your machine. Then you can install both your current ruby version and the one you wish to upgrade to. Switch between the two and test if your scripts are working. This should at least save you some time in the future.
solved Upgrading ruby 1.8.6 to ruby 1.9.2