def updates
      available.select do |spec|
        if wagon = installed_spec(spec.name)
          wagon.version < spec.version
        end
      end
    end
def updates
      available.select do |spec|
        if wagon = installed_spec(spec.name)
          wagon.version < spec.version
        end
      end
    end
Most recent gem specifications of available and installed (in an older version) wagons.