diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index c6e032d8d..3b0c6105c 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -1196,6 +1196,8 @@ struct usbi_os_backend {
 	 * claiming, no other drivers/applications can use the interface because
 	 * we now "own" it.
 	 *
+	 * This function gets called with dev_handle->lock locked!
+	 *
 	 * Return:
 	 * - 0 on success
 	 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
@@ -1215,6 +1217,8 @@ struct usbi_os_backend {
 	 * You will only ever be asked to release an interface which was
 	 * successfully claimed earlier.
 	 *
+	 * This function gets called with dev_handle->lock locked!
+	 *
 	 * Return:
 	 * - 0 on success
 	 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 208969c2c..6775980e4 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11867
+#define LIBUSB_NANO 11868