(let ((msg (and wl-draft-buffer-file-name
                            (string-match "[0-9]+$" wl-draft-buffer-file-name)
                            (string-to-int
-                            (elmo-match-string 0 wl-draft-buffer-file-name)))))
+                            (match-string 0 wl-draft-buffer-file-name)))))
              (wl-draft-config-info-operation msg 'delete))))
       (set-buffer-modified-p nil)              ; force kill
       (kill-buffer editing-buffer))))
   (wl-draft-config-info-operation
    (and (string-match "[0-9]+$" wl-draft-buffer-file-name)
        (string-to-int
-        (elmo-match-string 0 wl-draft-buffer-file-name)))
+        (match-string 0 wl-draft-buffer-file-name)))
    'save))
 
 (defun wl-draft-mimic-kill-buffer ()