[buddypress-dev] upgrade bp to 571 - sit_url() fatal error?

[C Daniel]

I just tried upgrading my BP and get an error when connecting 
PHP Fatal error: Call to undefined function: site_url() in /var/www/vhosts/httpdocs/wp-content/mu-plugins/bp-core/bp-core-avatars.php on line 19

any ideas?
 

Thanks