Latest update crashed website

Our client updated the plugin to latest version and it caused 500 internal server error. Seems like something hasn’t been finished.

This is what I have received when I tried deactivating plugin:

PHP Fatal error:  Uncaught Error: Call to undefined function wp_is_mobile() in /data/wordpress/shared/web/app/plugins/wp-chatbot/inc/commons/class-ht-cc-ismobile.php:39
Stack trace:
#0 /data/wordpress/shared/web/app/plugins/wp-chatbot/inc/commons/class-ht-cc-ismobile.php(27): HT_CC_IsMobile->is_mobile()
#1 /data/wordpress/shared/web/app/plugins/wp-chatbot/inc/class-ht-cc.php(120): HT_CC_IsMobile->__construct()
#2 /data/wordpress/shared/web/app/plugins/wp-chatbot/inc/class-ht-cc.php(99): HT_CC->basic()
#3 /data/wordpress/shared/web/app/plugins/wp-chatbot/inc/class-ht-cc.php(75): HT_CC->__construct()
#4 /data/wordpress/shared/web/app/plugins/wp-chatbot/wp-chatbot.php(28): HT_CC::instance()
#5 /data/wordpress/shared/web/app/plugins/wp-chatbot/wp-chatbot.php(31): ht_cc()
#6 /data/wordpress/shared/web/wp/wp-settings.php(268): include_once('/data/wordpress...')
#7 phar:///usr/local/bin/wp-cli/php/WP_CLI/Runner.php(1174): require('/data/wordpress...')
#8 phar:///usr/local/bin/wp-cli/php/WP_CLI/Runner.php(1100): WP_CLI\Runner->load_wo in /data/wordpress/shared/web/app/plugins/wp-chatbot/inc/commons/class-ht-cc-ismobile.php on line 39