diff --git a/README.markdown b/README.markdown
index fb2f630..80203b5 100644
--- a/README.markdown
+++ b/README.markdown
@@ -6,7 +6,7 @@ It allows update of the the microcontroller firmware over its serial port.
 
 The bootloader consists of two components, a piece of firmware that is flashed
 onto the device and a utility for downloading code and manipulating the
-flash memory.
+flash memory. The client program, `cctl-prog` runs on Linux, OSX/Darwin and Windows.
 
 Authors
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