This package is abandoned and no longer maintained. The author suggests using the guzzlehttp/guzzle package instead.
Kdyby/Curl requires PHP 5.3.2 or higher with cUrl extension enabled.
The best way to install Kdyby/Curl is using Composer:
$ composer require kdyby/curl:~2.2
Learn more in the documentation.
Homepage http://www.kdyby.org and repository http://github.com/kdyby/curl.