There is a newer major version of WordPress than the one your site runs. Only the newest version is sure to get every security update.
WordPress fixes holes in the newest version first. Older versions get fewer and later fixes, and after a while none at all. A site that stays behind slowly collects known holes.
This is part of the security check, a separate check next to the crawl, in Studio and Bureau, and only on a site you have verified. Snaglist only looks at what any visitor can see from outside. It never logs in, guesses no passwords and sends no attacks. It reads the WordPress version from the site and compares it with the newest version on wordpress.org.
In the report for your client this appears under the heading "Your WordPress is out of date". When everything is in order, the report says: "WordPress is up to date".
Snaglist checks every page of your site, for this issue and all the others. Start for free, no credit card needed.
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