To check the latest version of WordPress, go to Dashboard > Updates, which should be located at the top of the left sidebar of your WordPress admin area. WordPress will also usually send you an alert if a new version is available, shown in a box at the top of the page. You can also check, and download, the latest version of WordPress on the WordPress official website.
If you need some help keep your WordPress site maintained and updated, check out our WordPress Website Maintenance services.