diff --git a/README.md b/README.md
index 3694d29..cbbd3ff 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,8 @@
 # Introduction
 
+*Note*: Moonfire NVR is currently being rewritten from C++ into Rust. The text
+below describes the C++ version. See also the "rust" branch.
+
 Moonfire NVR is an open-source security camera network video recorder, started
 by Scott Lamb &lt;<slamb@slamb.org>&gt;. It saves H.264-over-RTSP streams from
 IP cameras to disk into a hybrid format: video frames in a directory on