An important note for everyone who's upgrading from PHP 5.4 and PHP 5.5, to PHP 5.6: the PHP default_charset in php.ini changed from "empty" to UTF-8, making UTF-8 the default charset in PHP. This may break HTML output if you try to set a different charset in your HTML head. It may also break functions like htmlentities() and htmlspecialchars. For example:

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UTF-8 encoding breaks when upgrading PHP 5.6 to PHP 7.0, fix PHP with ini_set( 'default_charset', "" ); or in your php.ini with default_charset = "".

Breaking HTML output with PHP 5.6 default_charset changed to UTF-8

Suppose you have the following lines in PHP code (don't ask me why you would want to do this...):

<html> 
<head> 
<meta http-equiv="content-type"
  content="text/html; charset=ISO-8859-1"> 
</head>
<body> 
<?php echo "éééééeeeeééé"; ?>
</body> 
</html>

The PHP default charset setting in PHP 5.4 and PHP 5.5 prints the expected string on the screen: éééééeeeeééé.

In PHP 5.6 however, the default_charset is set to UTF-8, changing PHP's default charset, and PHP 5.6 will always print a Content-Type response header set to UTF-8:

Content-Type: text/html; charset=UTF-8

The PHP default charset set to UTF-8 breaks HTML output and functions like htmlentities() / htmlspecialchars() (PHP bug #61354), because the HTML charset ISO-8859-1 is printed too (creating a double Content-Type response header):

GET -uUsSed http://www.example.com/echo.php
GET http://www.example.com/echo.php
User-Agent: lwp-request/2.07

GET http://www.example.com/echo.php --> 200 OK
Cache-Control: private
Date: Tue, 31 Mar 2015 12:03:50 GMT
Server: Microsoft-IIS/8.0
Content-Length: 141
Content-Type: text/html; charset=UTF-8
Content-Type: text/html; charset=ISO-8859-1
Client-Date: Tue, 31 Mar 2015 12:03:50 GMT
Client-Peer: 77.94.251.244:80
Client-Response-Num: 1

Don't turn off CURLOPT_SSL_VERIFYPEER, fix your PHP configuration

PHP.net writes:

If omitted, the default value of the encoding varies depending on the PHP version in use. In PHP 5.6 and later, the default_charset configuration option is used as the default value. PHP 5.4 and 5.5 will use UTF-8 as the default. Earlier versions of PHP use ISO-8859-1.

Although this argument is technically optional, you are highly encouraged to specify the correct value for your code if you are using PHP 5.5 or earlier, or if your default_charset configuration option may be set incorrectly for the given input.

PHP.net htmlspecialchars()

How to fix the HTML output in PHP 5.6 - and up (7.0, 7.1)

The most obvious solution to this problem is: don't set a character set encoding in your HTML meta tag, e.g:

<meta http-equiv="content-type"
  content="text/html; charset=ISO-8859-1">

Other options to set a correct default character set (default_charset) are:

Create an user-defined php.ini to overrule default_charset directive

PHP supports user-defined php.ini files, in which you can overrule some php.ini settings. Neat! Upload your user-defined php.ini to your webroot containing the following line:

default_charset = ""

This will tell PHP to not send a Content-Type response header set to UTF-8.

Overrule PHP's default_charset with ini_set()

And last but not least, you can overrule this setting with PHP's ini_set() function:

ini_set( 'default_charset', "" );
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Last updated on 16/07/2023

12 Comments

  2. Mihail
    11/07/2019,

    thank so much!

  3. Boris
    02/04/2019,

    Great post thank so much!

  4. Flaviu
    24/08/2018,

    Great! Thanks for the tip.

  5. Terratroz
    25/05/2018,

    Thank you

  6. Palle
    21/11/2017,

    Thanks but it should be:

    ini_set(‘default_charset’, ”);
    or
    ini_set(‘default_charset’, ‘none’);

    or you get an PHP Notice: Use of undefined constant default_charset – assumed ‘default_charset’

    • Jan Reilink
      21/11/2017,

      Well spotted Palle, thank you! The single quotes somehow got lost in that last piece of code, I’ve added them again.

  7. Anonymous
    22/09/2017,

    Thank you!!

  8. Anonymous
    09/07/2017,

    In PHP 7.0.19, the empty value of the default_charset directive (default_charset = “”) causes an error HTTP 500 “Internal Server Error”.
    You can solve this problem by setting the value to “none”. For example:
    php_value default_charset = none
    or
    php_value default_charset = “none”
    or
    php_value default_charset = ‘none’

    • Jan Reilink
      10/07/2017,

      Thanks! I’m about to set up PHP 7.0.20 (had to skip 7.0.19, now running .18) so I’ll keep this in mind and reply with my findings if necessary.

    • Abdulla Saeed
      16/04/2020,

      Thanks you ……
      I was searching about 2 days
      I used default_charset = “none”
      It Solved my php v7.4.4 application
      because i used iconv(‘windows-1256′,’utf-8’, $windowsArabicFileName )

      $windowsArabicFileName = “اسم ملف بالعربي.ppt”

  9. RemBem
    28/12/2016,

    Thank you, this saved my day, fixing an old site suddenly full of questionmarks after upgrading php. All your other website performance articles are also very helpful!

Comments are closed