dPlugins Collaboration made site crash out of nothing

Over night I received an email from my website that it has gone down, while nothing actually happened (auto updates are disabled). Investigation led to the dPlugins Collaboration plugin, which threw the following error: Uncaught Error: Call to undefined method GuzzleHttpUtils::chooseHandler() in /home/example/domains/example.com/public_html/wp-content/plugins/dplugins-collaboration/vendor/guzzlehttp/guzzle/src/functions.php:61 Stack trace: #0 /home/example/domains/example.com/public_html/wp-content/plugins/wp-seopress/vendor/guzzlehttp/guzzle/src/HandlerStack.php(42): GuzzleHttpchoose_handler() #1 /home/example/domains/example.com/public_html/wp-content/plugins/wp-seopress/vendor/guzzlehttp/guzzle/src/Client.php(65): GuzzleHttpHandlerStack::create() #2 /home/example/domains/example.com/public_html/wp-content/plugins/dplugins-collaboration/vendor/pusher/pusher-php-server/src/Pusher.php(69): GuzzleHttpClient->__construct() #3 […]

Collaboration