Unable to activate plugin in Wordpress 3.5.x

[hbel]

Wordpress: 5.3.2de
wpckan: Current master from git hub

Hi, there, I tried to install the plugin in a current wordpress installation but wasn't able to do so. I followed the installation steps as they we're described here, but as soon as I activate the plugin, wordpress, this leads to the following error:

Fatal error: Uncaught Error: Call to undefined method Guzzle\Common\Collection::fromConfig() in /var/www/html/wordpress/wp-content/plugins/wpckan/vendor/silex/ckan_client/src/Silex/ckan/CkanClient.php:33 Stack trace: #0 /var/www/html/wordpress/wp-content/plugins/wpckan/utils/wpckan-api.php(352): Silex\ckan\CkanClient::factory(Array) #1 /var/www/html/wordpress/wp-content/plugins/wpckan/utils/wpckan-utils.php(575): wpckan_api_ping() #2 /var/www/html/wordpress/wp-content/plugins/wpckan/wpckan.php(61): wpckan_validate_settings_read() #3 /var/www/html/wordpress/wp-includes/class-wp-hook.php(288): wpckan->check_requirements('') #4 /var/www/html/wordpress/wp-includes/class-wp-hook.php(312): WP_Hook->apply_filters(NULL, Array) #5 /var/www/html/wordpress/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #6 /var/www/html/wordpress/wp-admin/admin-header.php(281): do_action('admin_notices') #7 /var/www/html/wordpress/wp-admin/plugins.php(481): require_once('/var/www/html/w...') #8 {main} thrown in /var/www/html/wordpress/wp-content/plugins/wpckan/vendor/silex/ckan_client/src/Silex/ckan/CkanClient.php on line 33

By the way, guzzle is also marked as an orphaned and deprecated package according to output of composer.