Easy way to update Drupal website, we just have to follow some steps.
Step 1: Please take website full backup(files + database). We can use Backup and Migrate module ( https://www.drupal.org/project/backup_migrate )
Step 2: Site should be in maintanance mode because it can be broken updation time.
Step 3: Please take care of your patch code that already applied in core.
Step 4: Take a backup of Important files like 'robots.txt', '.htaccess', 'settings.php', 'web.config'. We will not update these files otherwise you will not get your old website.
Step 5: Now upload or override New version of drupal files except of given Step 4 files and 'modules','profiles','themes' folder because in new version these 3 folders will be empty.
Step 6: After full upload of files override Step 4 files.
Step 7: Clear the cache of website.
Step 8: Run update.php file via https://yourserver.com/update.php But by default this file is blocked, you have to enable this feature by setting.php file, go to setting.php file and change the option $settings['update_free_access'] = FALSE; to $settings['update_free_access'] = TRUE;
Step 9: After that save setting.php file and clear cache and hit https://yourserver.com/update.php after completion of process you can check you finally updation of site via https://yourserver.com/admin/reports/updates.
Note: If have any suggestions or issue regarding 'How can we update Drupal version?' then you can ask by comments.
