I just update my app from 5.3 to 5.4
I found that when my user is not logged and i go to a route that needs authentication my app trows the exception: "Call to undefined method App\Exceptions\Handler::unauthenticated()", i can fix the problem with some validation but i think that exist an error in the framework:
If you see the functions(unauthenticated()) seems that dissapear in the 5.4 but its still referenced in the Exceptions/Handler.php file:
vendor/laravel/framework/src/Illuminate/Foundation/Exceptions/Handler.php
line 114
} elseif ($e instanceof AuthenticationException) {
// You call the function unauthenticated but isn't exists
return $this->unauthenticated($request, $e);
if you see the same file in the 5.3 version this function actually exists Illuminate/Foundation/Exceptions/Handler.php line 186 (version 5.3):
protected function unauthenticated($request, AuthenticationException $e)
{
if ($request->ajax() || $request->wantsJson()) {
return response('Unauthorized.', 401);
} else {
return redirect()->guest('login');
}
}
Update:
I found that the unauthenticated function was moved in a fresh installation in the app/Exceptions/Handler.php file, I'm not sure if the function should exists in the vendor/laravel/framework/src/Illuminate/Foundation/Exceptions/Handler.php but at least i think that the upgrade guide should be updated to mention that.
I am having the same problem, the user is logged off when making a new request.
[2017-04-19 19:36:19] dev.ERROR: Illuminate\Auth\AuthenticationException: Unauthenticated. in /vendor/laravel/framework/src/Illuminate/Auth/GuardHelpers.php:39
Stack trace:
@alfonsobries have you looked at the migration guide? There are some changes in the exception handler
Please refer to the migration guide.
Im sorry i update from version 5.2 to 5.3 and then to 5.4, seems thats this reference is in the 5.2 to 5.3 guide, have a great day!

I having the same problem :( Can u show me your solution
I was looking into migration guide. Couldn't find any clue.
@themsaid you may take a deep look at it.
As @alfonsobries mentioned, it is in the 5.2->5.3 upgrade guide.
How to solve this error
FatalErrorException in Handler.php line 59:
Class 'App\Exceptions\SymfonyDisplayer' not found
@sanjeevmarichi
I have changed bit in Handler.php file. Here you go...
https://github.com/tisuchi/stricklands-fl/commit/9710b018369e07f82933ba59821024075689a13e#diff-646a4842abf9023c975a9a1658a68b0a
If there is no custom code in v5.2 app/Exceptions/Handlers.php then you can safely replace it with v5.3 app/Exceptions/Handlers.php.
Most helpful comment
@sanjeevmarichi
I have changed bit in Handler.php file. Here you go...
https://github.com/tisuchi/stricklands-fl/commit/9710b018369e07f82933ba59821024075689a13e#diff-646a4842abf9023c975a9a1658a68b0a