PHP Extensions and Settings

Which PHP versions and extensions KapsuleHost web hosting provides, which settings you can change yourself, and why a change can take up to five minutes to appear.

Everything to do with PHP for a site lives in one place: Websites, click the site, Advanced, then PHP. That page holds the version selector, the settings you can change, a Composer runner, and the PHP error log.

The PHP tab for a site in KPanel

Choosing a PHP Version

Four versions are selectable: 8.4, 8.3, 8.2 and 8.1. New sites default to 8.3.

Pick the newest version your software actually supports. Newer PHP is meaningfully faster and is supported with security fixes for longer. The reason not to jump straight to the newest is compatibility: an old plugin or a piece of custom code written years ago can fail outright on a version it has never been tested against.

To change it, select the version and click Apply Version. The change takes effect immediately, with no restart needed on your part and no downtime.

Change PHP version on staging first, click through the site, and only then change it on production. If you must do it live, do it when you can watch, and know that switching back is one click. See Staging Environments.

If a version change breaks the site, switch back to the previous version and read the log. The error will name the file that could not run. See Changing PHP Version and Error Logs.

Settings You Can Change

The PHP page exposes five settings as dropdowns. These are the ones that actually cause problems in practice, which is why they are the ones surfaced.

Setting	Default	Available values	What it controls
`memory_limit`	256M	128M, 256M, 512M, 1024M, 2048M	How much memory one request may use
`max_execution_time`	30	30, 60, 120, 300, 600	How many seconds one request may run
`upload_max_filesize`	64M	16M, 32M, 64M, 128M, 256M	The largest single file that can be uploaded
`post_max_size`	65M	17M, 33M, 65M, 129M, 257M	The largest total form submission
`max_input_vars`	3000	1000, 3000, 5000, 10000	How many fields one submission may contain

Which one you want:

Uploads failing above a certain size: raise upload_max_filesize, and post_max_size with it.
A large form or a page builder losing fields on save: raise max_input_vars. This one is invisible and infuriating, because nothing errors. The extra fields are silently discarded.
A page dying part way through with no error: raise memory_limit. See WordPress Memory Limit.
A long import or export timing out: raise max_execution_time, and consider running the job from the command line instead. See WP-CLI.

post_max_size must be larger than upload_max_filesize, because the upload travels inside the post. If you pick a combination where it is not, the platform corrects post_max_size up for you. That is why you may see a value you did not choose.

Why a Change Takes Up to Five Minutes

This is the single most common confusion on this page, so it is worth being precise.

Your settings are written to a .user.ini file in your site's document root. PHP reads that file and then caches it for 300 seconds, which is five minutes. Until that cache expires, PHP keeps using the previous values.

So after saving a change:

The page will still report the old limit for up to five minutes.
phpinfo() will still report the old limit for up to five minutes.
A hard refresh does not help. Neither does clearing your browser cache.
You do not need to restart anything, and you cannot. Just wait.

If it has been more than five minutes and the value has not changed, then something is genuinely wrong and it is worth a ticket.

Editing `.user.ini` Yourself

You can edit .user.ini directly over SFTP or SSH if you prefer, or if you need a directive the panel does not expose. It lives in your site's document root. See SFTP Access.

Format is one directive per line:

memory_limit = 512M
max_execution_time = 120

Two important limits on what .user.ini can do:

It only works for directives PHP allows to be set per directory or per user. The five above all qualify. Directives that can only be set at the system level, such as disable_functions or loading an extension with extension=, are ignored in a .user.ini file. They will not error, they will simply do nothing, which is why people spend an afternoon on them.

The panel only reads back simple keys. Directives containing a dot, such as opcache.enable or date.timezone, are honoured by PHP but will not appear in the panel form. If you set one by hand and later change something through the panel, check the file afterwards.

Kapsule web hosting runs nginx, not Apache. .htaccess files are read by nobody. PHP directives placed in a .htaccess file, such as php_value memory_limit, do absolutely nothing here. Use .user.ini or the panel instead. See WordPress and .htaccess.

Which Extensions Are Available

The standard build is broad and includes everything WordPress, WooCommerce and most PHP applications ask for.

Databases: mysqli, pdo_mysql, sqlite3, pdo_sqlite Images: gd, imagick, exif Caching: Zend OPcache, redis, memcached Text and locale: mbstring, iconv, intl, gettext, ctype XML and data: dom, simplexml, xml, xmlreader, xmlwriter, xsl, json Network: curl, soap, sockets, ftp, openssl Maths and crypto: bcmath, sodium, hash, random Files and system: fileinfo, zip, zlib, phar, posix, pcntl, shmop, calendar, tokenizer

One version difference worth knowing: the imap extension is present on 8.3 and earlier but not on 8.4, because it was removed from PHP itself in that release. If you have an application that still needs it, stay on 8.3 or move that application to a modern mail library.

Not installed: PostgreSQL drivers, MongoDB, Xdebug, mcrypt, and commercial code loaders such as ionCube and SourceGuardian.

You cannot enable or disable extensions yourself from the panel. If your application needs something that is not in the list, open a ticket and describe what you are running. Whether it can be added depends on the extension. See Opening a Support Ticket.

Checking What Is Actually Loaded

Rather than guessing:

On WordPress: Tools, then Site Health, then Info, then Server. It lists the PHP version and the relevant limits.
Over SSH: php -v for the version and php -m for the loaded extensions. See Adding SSH Keys.

Do not leave a phpinfo() file in your web root. It publishes your paths, your extensions and your configuration to anyone who finds it, and automated scanners look for exactly that filename. If you create one to check something, delete it immediately afterwards.