When any Drupal core updates are available, Drupal will display available updates in Available updates report. This report is available only when you enable the Update manager module.
This article explains how to update Drupal core.
Step (1). Take a backup of your site and its database.
Step (2). Log-in into your Drupal based website as an Administrator.
Step (3). Check for the available updates. Available updates can be found under Reports menu.
Step (4). Download the latest version from Download link.
Step (5). Log-in into your website’s control panel and upload the downloaded drupal zip file into the location where you have installed your website.
Step (6). Extract the files. Now your website is updated with Drupal core.
Step (7). Come back to your website’s admin area. Click on Report link. It will open Report page.
Step (8). Click on Status report link. It will display status report.
Step (9). Check for the status report and fix if any issues it shows. Usually it is required to update the database script. Click on database update script link under Database updates section.
Step (10). Follow the on-screen instructions to update any database updates.
Step (11). Make sure you apply any of your changes once you done with your Drupal core update.
by Code Steps