Just another day in the world of Ruby

From Ruby Inside:

Over the weekend, Rack 1.0.0 was released and… all hell broke loose on certain deployments (RubyFlow, for one). Passenger 2.2.1 had its own 1.0.0-esque vendorized version of Rack that conflicted with the all new Rack 1.0.0 and Rails 2.3.2 applications suffered severely.