Updating php 4 to 5
What it essentially comes down is that that web hosting companies don’t want to break their customers’ websites.
If your site is running on an older version of PHP, updating to the latest version will give you immediate performance gains—more so than any tweaking around the edges of your Word Press site will provide you with.
Then there’s PHP 7.0, which reached its end of life on December 3, 2018. Still, almost 20% of Word Press sites are on PHP 7.0. As with any software, PHP has a release life cycle that it needs to stick to in order to move forward with improvements and new features (just like Word Press).
If you’re thinking, “wasn’t PHP 7.0 just released?! Each major version of PHP is usually fully supported with bug patches and security fixes for two years after its release.
In early 2017 with the release of Yoast SEO 4.5, a notification was added to the Word Press dashboard for Yoast users.
It urged site owners whose sites were on a server running an outdated version of PHP to update to a new version.
In many cases, it’s up to developers and web hosts to push these site owners into upgrading (for their own good! For developers with older plugins and themes, updating to the latest versions of PHP involves updating their code, together with extensive testing to ensure compatibility.