Class 'GuzzleHttp\Client' not found A plugin that is using a Guzzle request is now throwing an exception that the class cannot be found.

I'm running Craft CMS 2.6.3000. Where is Guzzle being pulled from? I can see it within craft/app/vendor/guzzle and also within plugins/oauth/vendor but for some reason this plugin cannot cannot use this class anymore.

It is being referenced as $client = new \GuzzleHttp\Client();

Why can't the class be used?
Just a quick guess, but here is what I have on a project I am working on.    

$client = new \Guzzle\Http\Client();
$request = $client-&gt;get($url);


yours

$client = new \GuzzleHttp\Client();


mine

$client = new \Guzzle\Http\Client();


I have \Http\Client - maybe you are just missing the slash?