The theme of your site has a newer version on wordpress.org. A theme can have a hole too.
A theme contains code just like a plugin, and holes in it are fixed in new versions. An old theme also often blocks other updates, because it does not work with a newer WordPress or PHP.
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 recognises the theme by the addresses of its files, reads the version and compares it with the newest version on wordpress.org.
In the report for your client this appears under the heading "The theme is out of date". When everything is in order, the report says: "The theme 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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