How to Check Your WordPress Plugins and Theme Work With PHP 8.3

Key takeaways

• Make a list first. Site Health lists every active and inactive plugin and theme, with version and author. That list is your checklist.
• "Tested up to" is not about PHP. On WordPress.org it is the WordPress version the author tested with. It does not say the plugin was tested on PHP 8.3.
• "Requires PHP" is a floor, not a ceiling. It is the lowest PHP version the plugin needs. A plugin can meet it and still struggle on a newer PHP.
• WordPress.org's own advice is to test. Its update guide says well known, reputable plugins almost certainly work, and that they should still be tested. Back up first.
• Premium plugins need a question to the vendor. The WordPress.org guide does not cover them, so ask the seller in writing whether the current version supports PHP 8.3.
• A plugin that is not ready leaves you four options. Update it, contact the author, swap it for another, or postpone the PHP change.

The reason this matters now is covered in our main guide to the PHP vulnerability of October 2026. As of 22 October 2026, WordPress.org advises PHP 8.3 or newer, while php.net names 8.3.36 as the patched release for that branch.

Why plugins are the weak spot

When the host moves PHP to a newer release, WordPress core is usually ready. WordPress's compatibility page lists PHP 8.3 as supported in WordPress 6.4 through 7.1, and says 6.8 reached "fully compatible" in July 2025. It says nothing about plugins or themes, and that is the gap this guide fills. If you are below WordPress 6.4, update WordPress first. Not sure which PHP you run now? This walkthrough on checking and updating PHP in WordPress shows where to look.

Step 1: make your list in Site Health

WordPress's Site Health screen is the quickest way to get the full list.

1. From the dashboard menu, go to Tools and choose Site Health.
2. Click the Info tab.
3. Open Active Plugins, Inactive Plugins, Active Theme and Inactive Themes.

According to the WordPress.org page for this screen, each plugin entry shows its version, its creator and whether auto-updates are on. Themes show a name, version and author. The Server section shows your PHP version.

The Status tab warns if your site runs an outdated PHP or has plugins waiting to be updated.

Write the list down, with a column for what each plugin is used for and one for whether it is ready.

An inactive plugin or theme still counts. WordPress.org recommends removing inactive themes you do not plan to use, and the same sense applies to inactive plugins. Anything you delete is one less item to check.

Step 2: read the two fields on WordPress.org

Every plugin in the free directory has a page. Near the side of that page you will see "Requires PHP" and "Tested up to". Here is what the plugin developer handbook says they are, read 22 October 2026.

This is the point most owners miss. A plugin that says "Tested up to 7.0" has been tried on a recent WordPress. That is a good sign that the author is still active. It is not a statement about PHP 8.3.

The developer FAQ adds one more detail. The directory shows a "not tested" notice when the readme does not have a proper "Tested up to" value, and listing a WordPress version that has not been released also triggers it. So a notice on a plugin page is a prompt to look closer, but it is not proof of anything wrong with PHP.

The developer FAQ adds that the directory shows a "not tested" notice when the readme has no proper "Tested up to" value, so treat a notice as a prompt to look closer, not as proof of a PHP problem. The fields do help you rank plugins by risk.

The support forum on each plugin page is worth five minutes. If people have posted about errors on a newer PHP and nobody has replied, treat that as a warning.

Step 3: run a compatibility scan, then test by clicking

WordPress.org's update guide suggests installing the PHP Compatibility Checker plugin to scan your themes and plugins for possible problems. The same guide admits the plugin is imperfect: it can overlook real problems and also raise false alarms. So use it as a hint, not as a verdict.

Then do the check that matters most, which is to try it, on a staging copy of the site. That is a private duplicate where a mistake hurts nobody, and many hosts offer one.

On the staging copy, with PHP 8.3 selected, open the main pages, send the contact form, log in as a customer and as an administrator, place a test order if you sell, and open each plugin's settings. Watch for a blank white screen, a 500 error, or any message naming a plugin.

If you have no staging site, back up first and change PHP at a quiet time of day. Per WordPress.org, going back also requires your host to switch PHP down again, so confirm the host can do that fast.

Step 4: handle each kind of plugin

Once you have tried the site, every plugin on your list falls into one of these groups.

Abandoned plugins

WordPress.org's guide says to replace a plugin when the developer cannot or will not fix an issue, meaning another plugin that does the same job and is actively updated. Switching has its own cost, because settings and data may not carry over. A form plugin may need each form rebuilt, so plan that before the day your host changes PHP.

Premium plugins and themes

The WordPress.org update guide does not talk about premium products, so we cannot point you to an official rule. The sensible steps follow from the ones above:

1. Update to the latest version from the vendor's account page.
2. Look in the changelog or help centre for "PHP 8.3".
3. If it is not there, ask the vendor in writing. Something like: "Does version X of your plugin support PHP 8.3? If not, when is that planned?"
4. Keep the reply. If the plugin later breaks, it shows what you were told.

If the licence has expired, updates may be blocked, so check that first.

What to do when one is not ready

The options are to update it, contact the author or vendor, swap it for another plugin, or postpone the PHP change. Postponing only suits a plugin that runs something vital, such as checkout.

The last exit has a real cost. According to the php.net advisory, the PHP project will not ship an official fix for 8.1 or any older line. If you are on one of those versions, delaying leaves the server open. Before deciding to wait, look at the PHP end of life dates, and if the plugin powers your checkout, our notes on shops that run WooCommerce apply.

What is still unclear, and when this advice does not apply

• No official compatibility list for plugins. We could not find a WordPress.org page that lists which plugins work on PHP 8.3, so the checks above are the way to find out.
• Site Health does not test plugins on 8.3. The page we read describes its status messages and info panels. It does not describe a per plugin test for a newer PHP. Treat it as a way to get your list and your version.
• Your host decides the date. If the host changes PHP for you, you may have less time than you planned. Ask. We wrote up what to ask your host, and the piece on managed versus shared hosting explains who normally handles the patching.
• This is not for sites with no PHP. Static sites and hosted builders carry no WordPress plugins, so there is nothing to check.
• After a hack, check first. If you think the site was already compromised, read how to tell if your WordPress site is hacked before you change anything.

How we help at Amariq

Checking a plugin list line by line is slow, and the awkward part is the plugin that nobody has updated for years. Our team does this check as the first step of every PHP job, and we had already finished several of them within a day of the advisory. We write down each plugin, what the vendor says about PHP, and what we replace or leave alone. The whole job can come to us through the WordPress PHP update gig on Fiverr. We only need an administrator invite, because a password in a message is not something we accept. Fiverr and Upwork reviews are visible to everyone, and our YouTube channel has more on how we work.

Frequently asked questions

How can I tell whether a plugin works with PHP 8.3?

There is no single field that says so. Check the plugin's changelog and support forum for PHP 8.3, update to the latest version, and test it on a staging copy running 8.3. WordPress.org's guide also suggests a compatibility checker plugin, with the warning that it can be wrong.

What does "Tested up to" mean on a plugin page?

It is the WordPress version the author tested the plugin with. It is not the PHP version. A recent value suggests the author is still active, which is useful, but it does not prove PHP 8.3 support.

What does "Requires PHP" mean?

It is the lowest PHP version the plugin needs to run. A plugin that requires 7.4 may well work on 8.3, or it may not. The field does not say.

What if a premium plugin is not ready?

Ask the vendor in writing for a date and keep the answer. If there is none, find a maintained replacement, or move the site to a host plan where you can delay the change briefly. Do not sit on PHP 8.1 or older for long, because the PHP project has stopped fixing those lines.

Can I check this in Site Health?

Site Health lists your plugins, themes, versions and PHP version, and warns about outdated PHP and waiting plugin updates. The WordPress.org page we read does not describe a per plugin PHP 8.3 test, so use it to build your list.

Should I delete plugins I do not use?

Yes, if you are sure you do not need them. Fewer plugins means fewer things to check. Take a backup first.

Is it possible to hand this off?

Yes. A developer can do the backup, updates, switch and testing for you. Our guide on hiring someone to update PHP lists what to ask first, and the Fiverr service above covers the same steps for a fixed scope.