Fatal error: Class 'IntlDateFormatter' not found

if you see this on Debian / other Linux platforms.

sudo apt-get install php5-intl - for PHP 5.6

sudo apt-get install php7.0-intl - PHP 7+

Amazon Linux

sudo yum install php70-intl

After that restart Apache services.

sudo service apache2 restart restart apache to get the changes.

The extension was there! All you need to do is clearing the comment(;) before this line in php.ini file:

;extension=php_intl.dll

to

extension=php_intl.dll

in wamp or xampp open php.ini file and find the below line, then remove comment (;) at first of it:

;extension=php_intl.dll

if you did not find the line, add it in the php.ini file:

extension=php_intl.dll