WordPress 5.1 and the Notice About Your PHP Version

A new box on the dashboard

WordPress 5.1 was released today, and on sites running older versions of PHP it adds something new to the dashboard: a notice saying the site runs on an outdated version.

PHP is the programming language WordPress is written in. Your host runs it, and the version is set in the hosting account, not in WordPress.

Until now, WordPress said nothing about it. From this release, administrators on older versions see the notice near the top of the dashboard, with a button leading to an explanation of how updating works.

It is worth understanding before anybody acts on it, because the obvious response is the wrong one.

What the notice means

• It is not an error. The site works exactly as it did yesterday.
• It comes from WordPress itself, not from a plugin selling something.
• Only administrators see it. Visitors see nothing different.
• It is not a deadline, though the problem it describes only grows.
• Its absence proves nothing about whether your version is still supported.

The second is the one that matters on a typical site. Dashboards fill up with plugin notices asking for reviews and upgrades, and people learn to ignore all of them. This one is different in kind.

The last deserves a word too. WordPress.org decides which versions trigger the notice, and it has started with the oldest, so a site without it may still run a version that no longer receives security fixes.

Why WordPress is raising it now

Security support for PHP 5.6 ended on December 31, and for PHP 7.0 in January. A great many WordPress sites still run one of them, or something older.

WordPress cannot change the version itself. All it can do is tell the person who logs in, and as of today it does.

The same release also checks the PHP version a plugin says it needs, and declines to install one the server cannot run.

Over time, that is how an old version starts to show: plugins the site needs simply cannot be installed.

Who actually sees it

Only people who log in as administrators, and on many small business sites that is nobody at the business.

The designer who built the site may log in a few times a year. An owner who logs in to change a page passes the dashboard on the way and may never read it.

So it is worth asking directly. If your site runs WordPress, ask whoever maintains it whether the notice is showing, and what they plan to do about it.

The tempting shortcut

Most hosting control panels have a PHP version selector. On many, changing the version is a menu and a button, and it applies to the live site at once.

So the natural response to the notice is to log in to the hosting account, pick the newest version, press apply, and check that the home page still loads.

Usually it does. That is what makes the shortcut dangerous, because the home page is the least reliable test there is.

Why the home page proves nothing

Plugins and themes written years ago sometimes depend on functions that PHP 7 removed. When that code runs, the page stops with a fatal error: a blank screen or an error message.

Many sites also cache their pages, serving a saved copy rather than building each page fresh. A cached home page can look perfect after the switch, because the copy being shown was built before it.

Forms, bookings, searches and checkouts are not served from a cache. They run fresh every time, so they are where an incompatible plugin fails, and nobody checking the home page will see it.

The first person to find out is usually a customer whose enquiry went nowhere.

A worked example

Last autumn, the owner of a camera shop read an email from the shop's host recommending a move off PHP 5.6 before the end of the year.

The control panel made it easy: one menu, one button. The owner chose the newest version, opened the home page, saw it load normally, and went back to work.

The home page was cached. The lens rental booking form ran on a plugin last updated in 2015, which called a function PHP 7 had removed, and every booking submitted after the switch failed.

Four days passed before a regular customer phoned to ask why nobody had confirmed a lens booked for the weekend.

Switching back restored the form. Then came the proper upgrade: a current rental plugin installed on a copy of the site, every form tested on the new version, and the live site moved on a Monday evening.

How the upgrade should be handled

As a small project with an order, done by whoever maintains the site.

Update WordPress, the theme and every plugin first, and replace anything abandoned.

Then switch a copy of the site to the new version and test the pages that run fresh: every form sent for real, the booking or checkout through to the end, the search, the login.

Only then change the live site, outside business hours. Clear the cache, test the same pages again, and watch the error log for a week.

Which version to move to

PHP 7.2 or 7.3, whichever the site's plugins and theme are tested with. Version 7.1 loses security support in December, so choosing it means repeating the whole upgrade within the year.

A site still on PHP 5 has the largest jump to make, and the most old code waiting to be found.

The counter-case

Some sites have nothing to do.

A site already on 7.2 or 7.3 is in good shape, and the work is done.

A host that manages PHP versions and tests sites before switching them takes much of this off your hands, though it is worth asking exactly what their testing covers.

A site due to be rebuilt within weeks can reasonably move as part of the rebuild, provided the rebuild has a date.

For everyone else, treat the notice as a prompt to schedule the upgrade properly, not as a button to press.

When the notice appears

1. Leave the hosting panel alone for now.
2. Note the PHP version the site runs.
3. Tell whoever maintains the site.
4. Update everything else first.
5. Test the new version on a copy.
6. Send every form for real.
7. Switch the live site outside business hours.

Step six is the one the shortcut skips. A home page proves almost nothing about a PHP upgrade; a booking that arrives in the inbox proves the part that matters.

Finding the version and what depends on it is covered in the PHP version your site runs on.

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West Coast Media Solutions Inc. provides web design, web development, hosting, digital marketing, and business consulting to organisations across Canada, drawing on more than twenty-five years in the field.