You can check for available updates in the Status Report. The Status Report provides information about your installation, including the Drupal version, available module updates, pending security updates, whether your database is out-of-date, file security issues, missing dependencies and important information about PHP and your server environment. The Status Report also suggests solutions for issues as well as links to missing libraries.
To run and view the Status Report go to Administration > Reports > Status.
In Drupal 7 the Status Report can look like the images below.