Fatal error: Uncaught Error: Undefined class constant 'MAJOR_VERSION' in /home/swis0081/public_html/wp-content/plugins/google-calendar-events/vendor/guzzlehttp/guzzle/src/Utils.php:121 Stack trace: #0 /home/swis0081/public_html/wp-content/plugins/google-calendar-events/vendor/guzzlehttp/guzzle/src/functions.php(71): GuzzleHttp\Utils::defaultUserAgent() #1 /home/swis0081/public_html/wp-content/plugins/ed-school-plugin/includes/google-classroom/vendor/guzzlehttp/guzzle/src/Client.php(194): GuzzleHttp\default_user_agent() #2 /home/swis0081/public_html/wp-content/plugins/ed-school-plugin/includes/google-classroom/vendor/guzzlehttp/guzzle/src/Client.php(75): GuzzleHttp\Client->configureDefaults(Array) #3 /home/swis0081/public_html/wp-content/plugins/ed-school-plugin/includes/google-classroom/vendor/google/apiclient/src/Google/Client.php(1058): GuzzleHttp\Client->__construct(Array) #4 /home/swis0081/public_html/wp-content/plugins/ed-school-plugin/includes/google-classroom/vendor/google/apiclient/src/Google/Client.php(1032): Goo in /home/swis0081/public_html/wp-content/plugins/google-calendar-events/vendor/guzzlehttp/guzzle/src/Utils.php on line 121