After upgrade from 2.7 to 3.6.7 showing some error

I have done a cake php upgrade from 2.7.5 to latest version 3. but i have some issues, when i try to run bin/cake server it shows below errors.

PHP Warning: include(Cake/Console/ShellDispatcher.php): failed to open stream: No such file or directory in /var/www/project_1/bin/cake.php on line 31 PHP Warning: include(): Failed opening 'Cake/Console/ShellDispatcher.php' for inclusion (include_path='/var/www/lib:.:/usr/share/php') in /var/www/project_1/bin/cake.php on line 31

PHP Fatal error: Could not locate CakePHP core files. in /var/www/project_1/bin/cake.php on line 32

I can see the file cake.php which does not have any change but all other files moved from app to src folder, using cake php upgrade tool

If you are all updated, now create a new cakephp project and migrate your code to it, i.e., controllers, models, views, etc. Yes may take a little while.