Problem: you’re using Symfony2 with xampp and, when rendering some form with dates you get this error:
The Symfony\Component\Locale\Stub\StubIntlDateFormatter::setLenient() is not implemented. Please install the ‘intl’ extension for full localization capabilities.
To solve this, go to the xampp folder, php subfolder and edit the php.ini file.
In there, uncomment the line that says : extension=php_intl.dll i.e. enable that extension.
In the same php folder, select all dll’s named icu**46.dll and copy them over to the xamp/apache/bin folder.
Stop and Restart apache.
You’re welcome.