Non-static method CourseMember::getMembers() should not be called statically

Deprecated:  Non-static method CourseMember::getMembers() should not be called statically in /Users/tleilax/Code/studip/trunk/app/controllers/course/members.php on line 109
PHP Stack trace:
1. {main}() /Users/tleilax/Code/studip/trunk/public/dispatch.php:0
2. StudipDispatcher->dispatch($uri = '/course/members') /Users/tleilax/Code/studip/trunk/public/dispatch.php:27
3. StudipDispatcher->map_uri_to_response($uri = 'course/members') /Users/tleilax/Code/studip/trunk/vendor/trails/trails.php:121
4. Course_MembersController->perform($unconsumed_path = '') /Users/tleilax/Code/studip/trunk/vendor/trails/trails.php:154
5. Course_MembersController->perform($unconsumed = '') /Users/tleilax/Code/studip/trunk/app/controllers/studip_controller.php:119
6. Course_MembersController->index_action() /Users/tleilax/Code/studip/trunk/vendor/trails/trails.php:557