Not only an up-to-date WordPress will keep your website safe. The PHP scripting layer on your server needs updates as well to avoid serious security problems. Project Servehappy might be the push site owners need.
A few years back, there was a true war going on between webdesigners and deprecated browserversions. With notices all over the internet, internet users were advised to upgrade to a modern browser. In a short time, outdated browsers became a thing of the past… or at least the happy few. Servehappy would potentially do a similar thing.
Where Browsehappy had the internet user as primary target, Servehappy aims at the owner of the website. Thus the webdesigner indirectly. When logged in, the WP admin user would be shown a notice the website is running on a no longer supported version of PHP.
The notice should not only notify about the need to update, but also provide more information on what PHP is and why it is important to update. The notice would advise users to at least upgrade to PHP 5.2.x. By not suggesting a direct upgrade to PHP7, the team hopes webhosts don’t get too much pressure. There are still many plugins that are not compatible with PHP7 so upgrading every site to PHP7 could result in a lot of support requests.
Still, upgrading to PHP7 would be the smartest thing for many websites. PHP7 is much faster than PHP 5.2.x. This means websites increase in speed without investing in a faster webserver.