> Why are you blogging about upgrading to Rails 3.0.x when the current stable Rails has been 3.1.x for over 4 months?

They switched to 3.0 quite some time ago:

> Our production instances made the final switch in the week leading up to Thanksgiving

Writing this blog post probably wasn't very high priority.

> How did this happen?

Maybe they were busy creating a great product instead of obsessing about perfect architecture and optimising prematurely?