1 files changed, 12 insertions, 2 deletions

diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
index e1e742a1d72..66015475e4c 100644
--- a/lisp/mail/smtpmail.el
+++ b/lisp/mail/smtpmail.el
@@ -691,8 +691,18 @@ This is relative to `smtpmail-queue-dir'.")
                           (>= (car response-code) 400))
                       (throw 'done nil)))
               (dolist (line (cdr (cdr response-code)))
-                (let ((name (mapcar (lambda (s) (intern (downcase s)))
-                                    (split-string (substring line 4) "[ ]"))))
+                (let ((old-case-table (current-case-table))
+                      name)
+                  ;; Make sure we're using the standard case table
+                  ;; when downcasing; for instance, a downcased I is a
+                  ;; dotless i in Turkish.
+                  (unwind-protect
+                      (progn (set-case-table (standard-case-table))
+                             (setq name
+                                   (mapcar (lambda (s) (intern (downcase s)))
+                                           (split-string
+                                            (substring line 4) "[ ]"))))
+                    (set-case-table old-case-table))
                   (and (eq (length name) 1)
                        (setq name (car name)))
                     (and name