Fatal error: Class CI_Session_files_driver contains 2 abstract methods...

Fatal error: Class CI_Session_files_driver contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (SessionHandlerInterface::open, SessionHandlerInterface::close) in C:\xampp\htdocs\connectosh\system\libraries\Session\drivers\Session_files_driver.php on line 49

According to my observation, This is only a bug that is related to session class.

Solution : Below are the some solution that will differently be overcome this bug.

Step 1: Stop XAMPP (Apache server) and then start.

Step 2: If not working then install Codeigniter again and use it as a fresh one..

Step 3: Go to in C:\xampp\htdocs\test\system\libraries\Session\SessionHandlerInterface.php .
            And comment code this.

Hope!!! Now your code will be work.