WordPress Maintenance
How to Upgrade PHP on a WordPress Site Without Breaking It
A plain-English guide to upgrading PHP on WordPress: what to check first, how to test safely, and how to roll back if a plugin or theme breaks.
Upgrading PHP takes one click. Recovering from a bad upgrade can take a day.
The difference is preparation. Take a full backup, check that your theme and plugins support the new version, test on a copy of your site, and only then switch the live site. Keep a way back ready, and a problem costs you minutes instead of a bad afternoon.
So what exactly can break? How do you test safely? And when is it smarter to hand the job to someone else? You don't need to be a developer for the first half of this guide.
Why Your PHP Version Matters
PHP is the programming language WordPress runs on. Your hosting account uses one specific version, and your theme and plugins are written to work with certain versions.
Older versions eventually stop getting security fixes, while newer ones are better supported by current WordPress, themes, and plugins. At the time of writing, WordPress.org recommends hosting that supports PHP 8.3 or greater.
The catch: an old plugin, or a theme nobody has updated in years, may not work on a newer version. That's what "breaking" usually means: a white screen, a "critical error" message, or a feature that quietly stops working.
How To Prepare Before You Upgrade
None of these takes long, and together they remove most of the risk.
| Check | Why it matters |
|---|---|
| Full backup (files and database) | Your way back if anything goes wrong |
| Current PHP version, written down | You need to know where you're starting from |
| WordPress core, theme, and plugins updated | Updates often include fixes for newer PHP |
| List of active plugins | Tells you what to test afterwards |
| Staging copy | Lets you try the upgrade without visitors seeing it |
Find Your Current Version
In your WordPress dashboard, go to Tools → Site Health → Info, and open the Server section. It shows the PHP version your site uses right now. Your hosting control panel shows the same thing.
Make A Backup You Can Actually Restore
A backup only helps if you can restore it. Make sure it includes your site files and your database, and know where it's stored and how to restore it before you need it. If your host offers one-click restore points, find out how they work now, not during an emergency.
Spot Plugins And Themes That May Not Be Ready
Open each plugin's page in the WordPress plugin directory and check when it was last updated and which WordPress versions it was tested with. A plugin that hasn't been touched in a long time is a warning sign. So is a theme that no longer gets updates.
Found one? Decide now whether to replace it, ask its developer, or remove it. Don't discover it on the live site.
How To Upgrade PHP On WordPress, Step By Step
Step 1: Update Everything First
Update WordPress core, your theme, and your plugins before changing PHP. If a problem appears later, you'll know which change caused it.
Step 2: Test On A Staging Copy
A staging site is a private copy of your website. Many hosts offer one in the control panel, and plugins can do the same job. Switch the copy to the new PHP version and click through the pages that matter most: homepage, main service or product pages, contact forms, search, and checkout. Log in and open the editor too.
Step 3: Turn On Error Logging While You Test
If something looks off, WordPress can write errors to a log file. A developer can switch this on in the debug settings in wp-config.php. The log usually names the plugin or theme file causing trouble, which saves a lot of guessing. Turn it off when you're done, so visitors never see error details.
Step 4: Switch The Live Site At A Quiet Time
When staging looks good, change the version on the live site. In many hosting panels it's a simple dropdown, such as the MultiPHP Manager in cPanel; the exact name differs between hosts.
Choose a quiet time for your business. Avoid sales, campaigns, and late evenings when you'd struggle to fix anything.
Step 5: Test Again, Straight Away
Repeat the same click-through on the live site. Submit a contact form. Place a test order if you run a shop. Check the dashboard. Then check again a little later, because some problems only appear when a scheduled task runs.
Step 6: Know How To Go Back
If something important breaks and you can't fix it quickly, switch PHP back to the old version. The site comes back while you find the cause. This only works if you wrote the old version down.
Six steps, and the riskiest moment (step 4) happens only after you've already seen it work on a copy.
How To Handle What Usually Breaks
- A white screen or "critical error." Usually one incompatible plugin or theme. Switch back, then find the culprit using the error log or by deactivating plugins one at a time on staging.
- A feature stops working, but the site loads. Often a plugin failing quietly. Test forms, sliders, booking tools, and payment buttons.
- Warnings or notices on the page. Often harmless but unprofessional. Ask the plugin author for an update, or replace the plugin.
- Custom code that fails. Code written years ago may use features newer PHP no longer accepts. That one needs a developer.
How To Check The SEO Side Afterwards
A PHP upgrade doesn't change your content, but a broken site can affect search. After the switch:
- Open a few important pages and confirm they load normally.
- Make sure pages that used to work don't show server errors.
- Watch the indexing report in Search Console over the following days. Our guide on how to read the Google Search Console indexing report explains what you're looking at.
- Confirm your redirects, sitemap, and robots settings haven't changed.
We won't promise an upgrade improves rankings. The goal is a site that stays secure, supported, and working for visitors and search engines.
When It's Worth Getting Help
A simple site with a handful of well-known plugins is usually fine to do yourself. Get help when:
- Your site is a shop, membership site, or booking site, where a broken feature costs money
- You rely on custom code or an old theme
- Your host doesn't offer staging or easy rollback
- Nobody remembers who built the site or what's installed
If that sounds familiar, our PHP upgrade service handles the testing and rollback plan for you. Pricing is by quote, so just tell us about your site.
FAQ
Will upgrading PHP change how my site looks? Usually not. The design comes from your theme. A visible change normally means a theme or plugin isn't compatible.
Can I upgrade without a staging site? You can, but it's riskier. At least take a full backup, note your current version, and choose a quiet time.
Which PHP version is right for my site? It depends on your WordPress version, theme, and plugins. Check what they support, then test on staging. Your host can tell you which versions it offers.
Does a PHP upgrade fix a slow website? Sometimes it helps, but it's rarely the only cause. Slow mobile pages usually come from images, scripts, and layout; see Core Web Vitals in plain English.
Quick Checklist
- Current PHP version written down
- Full backup taken and restore tested
- Core, theme, and plugins updated
- Upgrade tested on staging
- Live switch done at a quiet time
- Forms, checkout, and dashboard re-tested
Wrapping Up
A PHP upgrade is low-risk when you can always go back. Write down your current version, take a backup you know how to restore, and test on a copy first.
If you'd like a second pair of eyes before you start, begin with a Free SEO Audit.
Sources
- WordPress requirements, WordPress.org