Display cases in contact summary tab in reverse order (ORDER BY id DESC)
I found quick hack to add sort in CRM_Case_Selector_Search class file. Though its not good practice to touch core, I could not find better option to get around this problem

  public function &amp;getRows($action, $offset, $rowCount, $sort, $output = NULL) {
       //adding sort here for descending
        $sort-&gt;_vars[1] = array('name'=&gt;'case_id',
                                'direction'=&gt;CRM_Utils_Sort::DESCENDING,
                                'title'=&gt;ts('Case ID')
                               );