Before changing the PHP version on a WordPress site, confirm the target version is supported by the current WordPress core, theme, plugins, and hosting environment. Then test the real visitor and administrative paths that would expose a compatibility failure, with a documented way back.
A PHP switch can look like one dropdown in a hosting panel, but it changes the runtime underneath WordPress. You need to check more than whether the setting changed. Can the site still do the work your business depends on with the new PHP version?
Check which versions your site supports
Record the current PHP version, intended version, WordPress version, active theme, active plugins, must-use plugins, and any custom code. Check vendor support for the exact versions you use. WordPress’s PHP guidance explains why supported PHP matters, but core compatibility doesn’t prove every extension on your site is ready.
Pay attention to old plugins that still appear quiet. A plugin can affect data, shortcodes, scheduled work, or integrations without owning an obvious page. If its purpose is uncertain, trace that dependency before combining removal with the PHP change.
Record the current setup and how to restore it
Take or confirm a current backup appropriate to the site, and make sure the person doing the work knows how to restore the required parts. Record the original PHP setting and any related server options. A screenshot is useful, but a rollback plan also needs the access, authority, and stopping condition required to act.
Run the change in a representative staging environment when the site’s risk justifies it. Compare the staging and production differences that could invalidate the test. If you can’t reproduce the hosting runtime or an important integration, keep that limitation visible and plan a smaller production window with faster checks.
Test jobs, not just pages
Open the homepage and a few important pages, but do not stop there. Log in, edit and preview content, submit a controlled form, use site search, inspect media, run the checkout or account path in an approved test mode, and exercise any scheduled or integration-driven work the business depends on.
Review logs and site health after the switch. A clean-looking homepage doesn’t rule out warnings, background failures, admin errors, or a broken route that only certain visitors use. Use the same completion discipline described in what to test after a WordPress update.
Change one major variable at a time
Do not pair the PHP switch with a plugin cleanup, theme replacement, and database migration unless they are inseparable and the combined change has been deliberately tested. With fewer changes at once, it’s easier to find what caused a failure and reverse the right change.
If the important paths pass, logs remain clean enough to explain, and the rollback window can close, record the new version and test evidence in the website change log. If not, return to the known state and investigate the specific failure. The goal is not to force the version change through; it is to make the supported change without turning the live site into the test environment.
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