can I run rails 4 on mongrel?

Question

I have just inherited an old rails 2.1 app that I would like to upgrade to rails 4. Their server setup is old and using ruby 1.8.6 and mongrel. There is a bit of a time crunch and I'd like to delay making major adjustments to the server itself right now. I can get to that later, but we need the rails 4 app up and running quickly. Basically we need to use ActiveMerchant which only supports back to 2.3.11. It seems silly to upgrade to that when I can just go to 4.

Can I run a rails 4 app on mongrel and 1.8.6?

Answer 1

No you can't. Rails 3 runs on >= 1.8.7. Rails 4 requires >= 1.9.3 and prefers 2.0.

The last Rails 2 app that I took to Rails 4, I found it easier to rebuild it, moving over piece by piece of functionality and rewriting/upgrading the code. It was fun, really, watching all those find :all calls go away.