intl extension: installing php_intl.dll

The package is already included in the extensions for PHP 7.2 and above and you just need to uncomment the following line in php.ini

extension=intl

I have PHP 5.3.1 and Apache

When I add the extension=php_intl.dll to php.ini and restart apache, it comes an alert that says "the requested operation has failed"

And this error on Event Monitor:

Faulting application name: httpd.exe, version: 2.2.14.0, time stamp: 0x4ac181d6
Faulting module name: php5ts.dll, version: 5.3.1.0, time stamp: 0x4b051b35
Exception code: 0xc0000005

The problem was some DLLs like icudt36.dll were missing (noticed with sysinternals ProcMon), I've downloaded php 5.3.1 zip version and extract all DLL's to PHP folder. That solved the problem.

You can type this command in terminal: sudo apt-get install php-intl

In my case adding PHP directory to PATH in user environment didn't work. After some testing I've found that it should be added to system PATH (I don't know what's the name of this part of system setting windows, 'couse I have Polish Windows).

I was having trouble getting intl to run using PHP 7.1.7 and PhpStorm on Windows 10. Based on other answers here I could tell it was a PATH/DLL dependency problem but I couldn't seem to find all of the required files even after (re-)installing the Visual C++ Redistributable.

I eventually went searching my C: drive for vcr*.dll and found a copy of vcruntime140.dll in my C:\Program Files\Mozilla Firefox directory. So, in addition to making these changes to php.ini:

extension_dir = "ext"
extension=php_intl.dll

I also set my runtime PATH to ONLY the PHP directory (in my case, C:\Program Files\PHP\7.1.7) and the Firefox directory (above) and it FINALLY worked! I know it needs more than just the vcruntime140.dll but the other required DLLs must be in the FF directory too (there are a few dozen but I didn't bother to figure out which ones are essential).

You have to modify the php.ini file by removing the semi-colon on the line containing extension=php_intl.dll

After this, go to the php folder of Xamp or Wamp or EasyPHP, copy every dll file containing icu*, Paste them inside your windows file.

That worked for me. Configuration : EasyPHP Dev Server, Windows 10.