Frequently asked questions

PHP 5.5, how does that work with Domainnameshop?

This FAQ entry has information aimed at both non-technical and technical users and developers.

Between November 2015 and January 2016, we upgraded all customers who hadn't already performed the upgrade from PHP 5.3 to PHP 5.5 themselves. This upgrade was free of charge.

PHP 5.5 is default for all webhotel Medium, Large and Extra Large since 1 September 2014.

If you experience problems you think are caused by our configuration or deficiencies with our servers, please first check that your software works with PHP 5.5, and that the tips below don't work out for you, before you contact support.


When will PHP 5.5 enter regular service?

PHP 5.5 entered regular service after 1 September 2014.

What does this FAQ entry answer?

This answer tries to cover some of the questions we think you may ask, or we have received questions about. We will update it as necessary.

What is different between the old and new webservers?

In brief, the new webservers are dedicated to serving PHP 5.5, they have more CPU power, more RAM, faster local storage, and a more recent and up-to-date operating system.

But what about the PHP differences?

There are several incompatible changes between PHP 5.3 and 5.5. You can find an overview on the PHP homepages. Because we skip PHP 5.4, the relevant changes is the union of changes from PHP 5.3 to 5.4, and from PHP 5.4 to 5.5. Most of the incompatible changes happened between PHP 5.3 and 5.5, and software made for PHP 5.4 will likely work well with PHP 5.5.

Here are direct links to the most important technical documents:

What is different in the configuration?

During the test phase, the following settings were enabled. These were be disabled 1 September 2014. You may enable these with your own .user.ini.

display_errors = On
display_startup_errors = On
track_errors = On

These settings were enabled by default in PHP 5.3, but are disabled for PHP 5.5:

short_open_tag = On
asp_tags = On
browscap = /etc/php5/php_browscap.ini

These settings have been changed or added:

date.timezone = Europe/Oslo
serialize_precision = 17
disable_functions = pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,
error_reporting = E_ALL & ~E_NOTICE & ~E_DEPRECATED & ~E_STRICT
variables_order = "GPCS"
request_order = "GP"
mail.add_x_header = On
session.use_strict_mode = 1
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=fakeentry"

pdo_mysql.cache_size = 2000

mysql.allow_local_infile = Off
mysql.cache_size = 2000

mysqli.max_persistent = -1
mysqli.allow_persistent = On
mysqli.cache_size = 2000
mysqli.default_pw =

These settings have been removed:

register_globals = Off
magic_quotes_runtime = Off
magic_quotes_sybase = Off
define_syslog_variables = Off
session.bug_compat_42 = 0
session.bug_compat_warn = 1

See also our overview of resource limits for other settings that differ.

What doesn't work with the PHP 5.5 webservers?

All PHP software that doesn't explicitly support PHP 5.4 will probably have problems. PHP software that doesn't explicitly support PHP 5.5 may have problems. Here are some concrete issues:

  • Very old modules, plugins, and themes for CMS-es like Joomla! and WordPress don't support PHP 5.5, check their documentation for details, and upgrade or replace out-dated software.
  • You cannot use our standard php.ini for PHP 5.3, it doesn't work with PHP 5.5, and generates an "Internal Server Error". Make your changes in .user.ini instead.
  • Software based on "short open tag", i.e. <? ... instead of <?php ... is not recognized as PHP.
  • Zend Guard is not installed for PHP 5.5. The product exists, and you may install it yourself.
  • ionCube Loader for PHP 5.5 (Linux 64-bits) works, but must be updated.
  • The webservers have a caching frontend based on Varnish. Image, CSS, and javascript updates may be delayed by up to 2 minutes.

May I have both PHP 5.3 and 5.5 on the same webhotel?

No, sorry, we cannot do that.

Can I downgrade to PHP 5.3 if PHP 5.5 doesn't work?

No, PHP 5.3 support is discontinued.

Can I test/use PHP 5.5 on SSH?

Yes, you can use as long as we offer PHP 5.5. To test the following version, PHP 5.6, use

My PHP program does not work, what could be wrong?

Lots of things can go wrong. In addition to what we have mentioned above, and all the usual potential issues mentioned in "The page cannot be displayed, what does the server error message mean?", there are several changes in PHP itself that may cause problems.

You may therefore enable debugging features in the configuration, so that you'll see error messages about PHP coding errors that themselves don't prevent PHP from starting.

What does Varnish do for my webhotel?

Varnish is a service between the visitor and the webserver itself.

Varnish briefly caches the content served by the webserver. This improves the response time for websites when there are several visitors within a short period of time, otherwise it is merely invisibly responding quickly to new connections.

Varnish is configured so that it doesn't cache websites with cookies. Please ensure that software/plugins/themes you use doesn't set cookies on the front page, or any other places you don't need cookies. Please also remember to follow the EU cookie directive, and inform your visitors in those cases where you have enabled cookies.

Combined with e.g. WP Super Cache (our recommendation), WordPress speeds up significantly for regular visitors. Logged-in visitors (those who are served cookies) are not cached to the same extent, so that all logged-in features work correctly.

Additionally, this frontend permits more responsive handling of several kinds of network and website attacks, so that website performance will suffer less than it does with our older platform that doesn't have Varnish.

See also:



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