After upgrading from CA 3 to 4 and completing migration, I get this fatal error:

Fatal error: Can't use method return value in write context in /home/domain/public_html/components/com_communityanswers/layouts/default/category_list.php on line 23

On the categories view (index.php?option=com_communityanswers&view=categories&id=0) or any of the available menu items

Any suggestions here please?