Error Exception

Criei o projeto com o comando informado no exercício para deixar a versão do laravel igual a do curso. Rodei o servidor com php artisan serve e funcionou, porém, ao abrir a página, ao invés da tela do Laravel, me deparei com uma série de erros:

ErrorException in Encrypter.php line 303: Function mcrypt_get_iv_size() is deprecated

    in Encrypter.php line 303
    at HandleExceptions->handleError('8192', 'Function mcrypt_get_iv_size() is deprecated', '/home/natan/Projetos WEB/estoque/vendor/laravel/framework/src/Illuminate/Encryption/Encrypter.php', '303', array()) in Encrypter.php line 303
    at Encrypter->updateBlockSize() in Encrypter.php line 280
    at Encrypter->setCipher('rijndael-128') in EncryptionServiceProvider.php line 20
    at EncryptionServiceProvider->Illuminate\Encryption\{closure}(object(Application), array()) in Container.php line 776
    at Container->build(object(Closure), array()) in Container.php line 659
    at Container->make('encrypter', array()) in Application.php line 644
    at Application->make('encrypter') in Container.php line 890
    at Container->resolveClass(object(ReflectionParameter)) in Container.php line 851
    at Container->getDependencies(array(object(ReflectionParameter)), array()) in Container.php line 815
    at Container->build('Illuminate\Cookie\Middleware\EncryptCookies', array()) in Container.php line 659
    at Container->make('Illuminate\Cookie\Middleware\EncryptCookies', array()) in Application.php line 644
    at Application->make('Illuminate\Cookie\Middleware\EncryptCookies') in Pipeline.php line 124
    at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in CheckForMaintenanceMode.php line 42
    at CheckForMaintenanceMode->handle(object(Request), object(Closure)) in Pipeline.php line 125
    at Pipeline->Illuminate\Pipeline\{closure}(object(Request))
    at call_user_func(object(Closure), object(Request)) in Pipeline.php line 100
    at Pipeline->then(object(Closure)) in Kernel.php line 115
    at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 84
    at Kernel->handle(object(Request)) in index.php line 52
    at require_once('/home/natan/Projetos WEB/estoque/public/index.php') in server.php line 21

Como faço para prosseguir?