Upgrading Your Website's PHP Version Safely: Why Old PHP Is a Risk

PHP is the programming language behind a large share of business websites — custom PHP sites, WordPress, many e-commerce platforms. Like any software, each PHP version has a limited support life. After that, it no longer receives security fixes. Yet many small business websites keep running on old versions for years because "it still works".

It does still work — until a vulnerability is exploited, or the hosting company removes the old version and the website suddenly breaks. Upgrading on your own schedule is far better than being forced to in an emergency.

Why it matters

• Security: unsupported versions don't get patches for newly discovered vulnerabilities.
• Speed: PHP 8.x is generally faster than PHP 7.x and much faster than 5.x for the same code.
• Compatibility: newer plugins, libraries and payment SDKs often require recent PHP.
• Hosting changes: hosts eventually stop offering very old versions.

PHP support timeline (as of late 2026)

Check the official PHP "Supported Versions" page for current dates before planning.

Step 1: Find your current version

On Hostinger, look in hPanel under the website's Advanced → PHP Configuration section. In cPanel, look for "Select PHP Version" or "MultiPHP Manager". Developers can also create a temporary file with <?php phpinfo(); — but delete it immediately afterwards, as it exposes server details.

Step 2: Take a full backup

Files and database, downloaded to your computer. If anything goes wrong, you can switch back the PHP version and restore. See our backup guide.

Step 3: Check for common compatibility problems

Code written for old PHP may use features that were removed or changed. Common examples:

• mysql_* functions (removed in PHP 7) — must be replaced with mysqli or PDO.
• each(), create_function() — removed.
• Curly-brace string offsets like $str{0} — removed in PHP 8.
• Stricter errors in PHP 8: passing null to string functions, undefined array keys and wrong argument types now produce warnings or fatal errors that were silent before.
• Old libraries — PHPMailer, payment SDKs or WordPress plugins that haven't been updated.
• Dynamic properties on classes are deprecated from PHP 8.2.

Developers can run tools such as PHPCompatibility (with PHP_CodeSniffer) to scan code automatically.

Step 4: Test on a copy first

1. Create a staging copy — a subdomain like test.yourbusiness.com with a copy of the files and database.
2. Set the staging site to the new PHP version.
3. Turn on error logging (not on-screen display) and click through every page and form.
4. Test admin login, image uploads, payments, emails and any cron jobs.
5. Check the error log for warnings and fix them. See reading website error logs.

On small sites without a staging option, you can switch the live version at a quiet time and switch back immediately if something breaks — but only with a fresh backup.

Step 5: Upgrade one step at a time

Jumping from PHP 5.6 straight to 8.4 can surface many problems at once. For very old sites, move to a 7.4-compatible state first, then to 8.x. For WordPress, update core, theme and plugins before changing PHP.

Step 6: Monitor after the switch

Keep an eye on the error log for a week. Submit test enquiries. Ask staff to report anything unusual in the admin panel.

When a rebuild makes more sense

If a site is built on very old code with no documentation, uses removed functions everywhere, and has no developer who understands it, fixing it may cost more than rebuilding cleanly. A modern rebuild also brings speed, mobile design and SEO improvements. See signs you need a redesign.

Frequently Asked Questions

Will upgrading PHP break my website?

It can if the code uses removed features. That's why backup and testing come first. Well-maintained code usually upgrades smoothly.

Does PHP version affect SEO?

Not directly, but faster page generation and fewer errors help user experience and crawling.

How often should PHP be updated?

Plan a review every year and stay on a supported version.

Can I upgrade WordPress sites the same way?

Yes. Update WordPress, theme and plugins first, then switch PHP and test.

Need a safe PHP upgrade?

Joboo Web updates legacy PHP code and modernises websites. See web development, our maintenance checklist, or contact us.