diff --git a/scripts/codegen/run_trunnel.sh b/scripts/codegen/run_trunnel.sh
index df84a6e2a..5f694ce6c 100755
--- a/scripts/codegen/run_trunnel.sh
+++ b/scripts/codegen/run_trunnel.sh
@@ -5,7 +5,7 @@ if test "x$TRUNNEL_PATH" != "x"; then
   export PYTHONPATH
 fi
 
-python -m trunnel ./src/trunnel/*.trunnel
+python -m trunnel --require-version=1.2 ./src/trunnel/*.trunnel
 
-python -m trunnel --write-c-files --target-dir=./src/ext/trunnel/
+python -m trunnel --require-version=1.2 --write-c-files --target-dir=./src/ext/trunnel/
 
diff --git a/src/ext/trunnel/trunnel-impl.h b/src/ext/trunnel/trunnel-impl.h
index 4dd710f4a..c88ee3988 100644
--- a/src/ext/trunnel/trunnel-impl.h
+++ b/src/ext/trunnel/trunnel-impl.h
@@ -1,3 +1,7 @@
+/* trunnel-impl.h -- copied from Trunnel v1.2
+ * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
+ */
 /* trunnel-impl.h -- Implementation helpers for trunnel, included by
  * generated trunnel files
  *
diff --git a/src/ext/trunnel/trunnel.c b/src/ext/trunnel/trunnel.c
index 4bc28e3f0..da4885ca0 100644
--- a/src/ext/trunnel/trunnel.c
+++ b/src/ext/trunnel/trunnel.c
@@ -1,3 +1,7 @@
+/* trunnel.c -- copied from Trunnel v1.2
+ * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
+ */
 /* trunnel.c -- Helper functions to implement trunnel.
  *
  * Copyright 2014, The Tor Project, Inc.
diff --git a/src/ext/trunnel/trunnel.h b/src/ext/trunnel/trunnel.h
index 0a78e6cfc..f51cade03 100644
--- a/src/ext/trunnel/trunnel.h
+++ b/src/ext/trunnel/trunnel.h
@@ -1,3 +1,7 @@
+/* trunnel.h -- copied from Trunnel v1.2
+ * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
+ */
 /* trunnel.h -- Public declarations for trunnel, to be included
  * in trunnel header files.
 
diff --git a/src/trunnel/pwbox.c b/src/trunnel/pwbox.c
index 0fbbf2eb6..b70e1d826 100644
--- a/src/trunnel/pwbox.c
+++ b/src/trunnel/pwbox.c
@@ -1,5 +1,6 @@
-/* pwbox.c -- generated by Trunnel v1.1-dev.
+/* pwbox.c -- generated by Trunnel v1.2.
  * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
  */
 #include <stdlib.h>
 #include "trunnel-impl.h"
diff --git a/src/trunnel/pwbox.h b/src/trunnel/pwbox.h
index 84bbdf3a8..5b170eb45 100644
--- a/src/trunnel/pwbox.h
+++ b/src/trunnel/pwbox.h
@@ -1,5 +1,6 @@
-/* pwbox.h -- generated by by Trunnel v1.1-dev.
+/* pwbox.h -- generated by by Trunnel v1.2.
  * https://gitweb.torproject.org/trunnel.git
+ * You probably shouldn't edit this file.
  */
 #ifndef TRUNNEL_PWBOX_H
 #define TRUNNEL_PWBOX_H