I get this debug error notice: "Strict Standards:

Hello,

I get this debug error notice:
"Strict Standards: Declaration of BP_Group_Calendar_Extension::display() should be compatible with BP_Group_Extension::display($group_id = NULL) in /nas/wp/www/cluster-41320/spiritberlin/wp-content/plugins/bp-group-calendar/groupcalendar/bp-group-calendar.php on line 102"

Do you know how i can fix this?

Best,
Jacob