Understanding PHP Version Compatibility

Every PHP release makes sites faster and safer, but it also removes old functions and turns bad habits into warnings or errors. That's why a site can break when you switch PHP versions. This guide explains which PHP versions are still supported in 2026, what changed between them, and how to test your site before you switch on Domain India hosting.

1. Which PHP versions are supported in 2026

Under the release policy PHP adopted in 2024, each version gets two years of active support and then two years of security fixes, ending on 31 December. The status on 23 September 2026:

An end-of-life version gets no security fixes, even for serious holes. If your site runs 8.1 or older, plan the upgrade now. If it runs 8.2, plan it before the end of 2026.

2. What Domain India offers

Measured on our shared servers in September 2026:

• cPanel: PHP 5.1 to 8.5, chosen per domain in MultiPHP Manager. New accounts use 8.3.
• DirectAdmin: PHP 5.6, 7.2, 7.3, 7.4, 8.1, 8.2 and 8.3, chosen per domain.
• Webuzo: not measured; ask support.

Because the version is set per domain, you can test a new version on a copy of your site without touching the live one (see section 5).

3. What changed between versions

These are the changes that most often break real sites. The official PHP migration guides list every change.

PHP 7.0: the old MySQL functions went

mysql_connect() and every other mysql_* function were removed. Very old scripts that still use them fail on every PHP 7 and 8 version.

// Removed
$conn = mysql_connect($host, $user, $pass);

// Use mysqli or PDO instead
$conn = new PDO("mysql:host=$host;dbname=$db", $user, $pass);

PHP 8.0: removals and stricter behaviour

• each(), create_function() and money_format() were removed. Replace while (list($k, $v) = each($arr)) with foreach ($arr as $k => $v).
• Many warnings became errors: for example, count() on something that isn't an array or countable object now throws a TypeError.
• Comparing a number with a non-numeric string changed: 0 == "foo" is now false. Use === where the type matters.

PHP 8.1: deprecations that fill logs

• Passing null to a built-in function that expects a string, such as strlen(null) or trim(null), is deprecated. This is the most common notice from older WordPress plugins.
• strftime() and FILTER_SANITIZE_STRING are deprecated. Use date() or IntlDateFormatter, and htmlspecialchars().
• New features include enums, readonly properties and fibers.

PHP 8.2: dynamic properties

Setting a property that a class never declared is deprecated:

class User {
    public string $name;   // declare it, and the notice goes away
}

utf8_encode() and utf8_decode() are deprecated too; use mb_convert_encoding().

PHP 8.3, 8.4 and 8.5

• 8.3 has few breaking changes. It adds typed class constants and json_validate().
• 8.4 deprecates implicitly nullable parameters: write ?Type $x = null instead of Type $x = null. It also moved the IMAP, OCI8 and Pspell extensions out of PHP's core, so scripts that read mailboxes with imap_open() should be checked. New features include property hooks and asymmetric visibility.
• 8.5 adds the pipe operator (|>) and a built-in URI extension, with a further set of deprecations; read its migration guide before you switch custom code.

4. Check your code before you switch

• WordPress, Joomla and other CMSs: update the core, every plugin and the theme first. Most compatibility problems are fixed by an update; a plugin that hasn't been updated in years is the usual culprit. Check each plugin's page for the PHP versions it supports.
• Custom code: run a static analyser such as PHPStan or Rector on your own computer, set to the PHP version you plan to use. Run these tools locally: some PHP functions they depend on are disabled on shared hosting (see PHP disabled functions on shared hosting).
• Frameworks: Laravel, Symfony and similar frameworks state a minimum PHP version for each release. Upgrade the framework and the PHP version together.

5. Test the new version safely

To confirm which version a site runs, upload a file containing <?php echo PHP_VERSION;, open it, then delete it. phpinfo() is disabled on our cPanel servers.

6. If the site breaks after the switch

• 500 error or blank page: switch the domain back to the previous version first, so the site works again. Then find the cause in the error log. See Troubleshooting 500 Internal Server Error.
• "Call to undefined function": the function was removed. Update the plugin or code that calls it.
• A missing extension: open a ticket with the extension name and the PHP version.

Upgrade one step at a time where you can, for example 7.4 to 8.1, then to 8.3, so each problem is smaller and easier to trace.

7. Where Domain India fits

cPanel hosting gives you the widest choice, from legacy PHP 5.x for an old script to PHP 8.5 for new work, switchable per domain. DirectAdmin offers PHP up to 8.3. The card shows the current list price; 18% GST is added at checkout.

If you need a PHP version or extension that shared hosting doesn't offer, a VPS gives you full control.

Ready to upgrade? Follow How to change your PHP version, open your hosting services to reach your control panel, or open a support ticket if you need help planning the switch.