Failed to change administration password : SQL set password for 'root'@'127.0.0.1' ....Please use mysql_upgrade to fix this erro

Failed to change administration password : SQL set password for ‘root’@‘127.0.0.1’ = password(‘eieE9’) failed : Column count of mysql.user is wrong. Expected 42, found 39. Created with MySQL 50173, now running 50562. Please use mysql_upgrade to fix this error.

How to upgrade mysql ?