When a new version of WordPress is released, or a theme or plugin installed on your site has an update ready, a link with an update icon will be displayed in the admin bar of your site. The number next to the icon shows the number of updates currently available. When you click the link, you’re taken to the WordPress Updates screen. Here, you can see all updates that are ready to be installed.
- To update WordPress itself, click the blue “Update Now” button below the “An Updated Version of WordPress is Available” heading.
- To update plugins, check the plugin you want to update and click the “Update Plugins” button.
- To update themes, check the themes you want to update and click the “Update Themes” button.
As a general rule, you should always have the latest version of WordPress itself and the plugins and themes you use. Updates can include useful new features and functionality, but more importantly, they include updates that patch security vulnerabilities. If you haven’t updated your WordPress installation in the last year, there’s a high likelihood that it has at least a couple of vulnerabilities that can be exploited by malicious parties.
As always, there are exceptions to the rule. If you have made changes directly to your theme files, those changes will be overwritten when the theme is updated. To avoid this problem, you should use either the Custom CSS setting in the customizer, or include your changes in a child theme. There is also the risk that updates to themes or plugins will remove or change functionality that you’re currently dependent on. If you feel uncertain, you should try to contact the developer of the theme or plugin to find out what changes are included.
Those exceptions do not apply to WordPress core, though. You should always be running the latest version of WordPress. Since WordPress 3.7, WordPress supports automatic updates of WordPress itself, plugins, themes and translations. By default, the automatic updates feature is only activated for minor updates of WordPress core (like maintenance and security releases). You can use the WP Automattic Updates plugin to configure automatic updates on your site.