diff --git a/emacs/notmuch-mua.el b/emacs/notmuch-mua.el
index ac2d29ec..24eebffa 100644
--- a/emacs/notmuch-mua.el
+++ b/emacs/notmuch-mua.el
@@ -146,7 +146,7 @@ list."
   (unless (bolp) (insert "\n")))
 
 (defun notmuch-mua-reply (query-string &optional sender reply-all)
-  (let ((args '("reply" "--format=json"))
+  (let ((args '("reply" "--format=json" "--format-version=1"))
 	reply
 	original)
     (when notmuch-show-process-crypto
diff --git a/emacs/notmuch-query.el b/emacs/notmuch-query.el
index e7e35207..6e9f406d 100644
--- a/emacs/notmuch-query.el
+++ b/emacs/notmuch-query.el
@@ -29,7 +29,7 @@ A thread is a forest or list of trees. A tree is a two element
 list where the first element is a message, and the second element
 is a possibly empty forest of replies.
 "
-  (let ((args '("show" "--format=json")))
+  (let ((args '("show" "--format=json" "--format-version=1")))
     (if notmuch-show-process-crypto
 	(setq args (append args '("--decrypt"))))
     (setq args (append args search-terms))
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index b0fd387e..63387a2d 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -650,6 +650,10 @@ of the result."
 		      (insert "Incomplete search results (search process was killed).\n"))
 		  (when (eq status 'exit)
 		    (insert "End of search results.\n")
+		    ;; For version mismatch, there's no point in
+		    ;; showing the search buffer
+		    (when (or (= exit-status 20) (= exit-status 21))
+		      (kill-buffer))
 		    (condition-case nil
 			(notmuch-check-async-exit-status proc msg)
 		      ;; Suppress the error signal since strange
@@ -935,7 +939,7 @@ Other optional parameters are used as follows:
 	(let ((proc (start-process
 		     "notmuch-search" buffer
 		     notmuch-command "search"
-		     "--format=json"
+		     "--format=json" "--format-version=1"
 		     (if oldest-first
 			 "--sort=oldest-first"
 		       "--sort=newest-first")
diff --git a/test/emacs b/test/emacs
index 5067d67b..6b189688 100755
--- a/test/emacs
+++ b/test/emacs
@@ -873,7 +873,7 @@ This is output
 Error: Unexpected output from notmuch search:
 This is an error
 End of search results.
-Error invoking notmuch.  $PWD/notmuch_fail search --format=json --sort=newest-first tag:inbox exited with status 1."
+Error invoking notmuch.  $PWD/notmuch_fail search --format=json --format-version=1 --sort=newest-first tag:inbox exited with status 1."
 
 
 test_done
diff --git a/test/emacs-show b/test/emacs-show
index 40fab616..ebf530bc 100755
--- a/test/emacs-show
+++ b/test/emacs-show
@@ -178,7 +178,7 @@ test_emacs "(let ((notmuch-command \"$PWD/notmuch_fail\"))
 	       (with-current-buffer \"*Notmuch errors*\"
 		  (test-output \"ERROR\")))"
 test_expect_equal "$(cat OUTPUT ERROR)" "\
-Error invoking notmuch.  $PWD/notmuch_fail show --format=json --exclude=false ' * ' exited with status 1.
+Error invoking notmuch.  $PWD/notmuch_fail show --format=json --format-version=1 --exclude=false ' * ' exited with status 1.
 Error:
 This is an error
 Output: