Upgradation to meteor 1.5 ( Iron Router throws a error fn() is not defined

Upgradation to meteor 1.5 ( Iron Router throws a error fn() is not defined. )
I see all the Iron router packages are updated…

**Exception in callback of async function: TypeError: fn is not a function**
**_ at http://localhost:3000/packages/iron_controller.js?**hash=eb63ea93809dcd3a8f40ad258e0997969a4d3ebc:133:22_
_ at Tracker.Computation.compute (http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:339:36)
_ at new Tracker.Computation (http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:229:10)_
_ at Object.Tracker.autorun (http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:613:11)_
_ at http://localhost:3000/packages/iron_controller.js?hash=eb63ea93809dcd3a8f40ad258e0997969a4d3ebc:131:21_
_ at Object.Tracker.nonreactive (http://localhost:3000/packages/tracker.js?hash=997515fa2d5b0530ba07741da556c4b36963ef3b:640:12)_
_ at WaitList.wait (http://localhost:3000/packages/iron_controller.js?hash=eb63ea93809dcd3a8f40ad258e0997969a4d3ebc:124:8)_
_ at ctor.Controller.wait (http://localhost:3000/packages/iron_controller.js?hash=eb63ea93809dcd3a8f40ad258e0997969a4d3ebc:440:20)_
_ at eachWait (http://localhost:3000/packages/iron_controller.js?hash=eb63ea93809dcd3a8f40ad258e0997969a4d3ebc:435:12)_
_ at Array.forEach ()_

In Tracker.js

Tracker.Computation.prototype._compute = function () { // 302
var self = this; // 303
self.invalidated = false; // 304
// 305
var previous = Tracker.currentComputation; // 306
setCurrentComputation(self); // 307
var previousInCompute = inCompute; // 308
inCompute = true; // 309
try { // 310
withNoYieldsAllowed(self._func)(self); // 311
} finally { // 312
setCurrentComputation(previous); // 313
inCompute = previousInCompute; // 314
} // 315
};

Disclaimer: I don’t use IR. However, I do recall some update issues which were solved by examining the IR package versions with the actual latest version numbers and updating those explicitly.

You could try using meteor update --all-packages first to see if that helps.