I haven’t upgraded my Ruby On Rails and related Ruby gems for 5 months. One of the reasons is that Rails development team likes to break the backward compatibility, such as:
NameError: uninitialized constant ApplicationController
To avoid this kind of surprises, I tend to stick with a working, stable version.
Recently, I upgrade the entire Ruby On Rails family(2.3.2 -> 2.3.4), and surprisingly, my Ruby On Rails apps work perfectly fine! One exception is that the Mongrel server behaves a little bit slower than before. One way or the other, we need to use the load balancing technique to host the Rails App anyway. So it really doesn’t matter.
In case you want to try upgrading your Ruby Gems and other things:
Update the Ruby Gem Engine:
sudo gem update --system
Update other Ruby Gems:
sudo gem update