Fatal error after updating plugins

I updated the the wpmudev plugins successfully according to the wpmudev dashboard as it flicked back to the main dashboard i got this error
Fatal error: Call to undefined function bp_get_root_blog_id() in /home/webfxcz/public_html/native-speaker.cz/wp-content/plugins/buddypress/bp-core/bp-core-wpabstraction.php on line 57

now i am unable to access the site at all