When a new wordpress version is available, you will see a notification in the WordPress admin area for update your wordpress website. Please make sure before the update your wordpress version because after successfully upgradation you can’t Go Back to Old Versions.
Backup Your Database and all WordPress files in your root directory. Don’t forget your .htaccess file.
Step-2 Deactivate ALL your Plugins
In your wordpress admin panel go to the “Plugins->Installed Plugins”. Now deactivate all your exiting plugins.
Step-3 If you experience difficulties with login after your upgrade, it is worth clearing your browser’s cookies.
Now click on your blog’s Upgrade Page (http://yourwebname.com/wp-admin/upgrade.php) and follow the instructions that are displayed there.
After the successfully wordpress updates you will get the below screen.
If you get the difficulties with login after your wordpress upgradation, it is worth clearing your browser’s cookies.