Please be aware, that there are issues when using the Facebook SDK together with Guzzle 6.x. php-graph-sdk v5.x only works with Guzzle 5.x out of the box. However, there is a workaround to make it work with Guzzle 6.x. Upgrading to v5.x. Upgrading from v4.x? Facebook PHP SDK v5.x introduced breaking changes.

