diff --git a/doc/crawler.md b/doc/crawler.md
index d4f88b25..0adab8bc 100644
--- a/doc/crawler.md
+++ b/doc/crawler.md
@@ -21,6 +21,7 @@ The ultrapeer responds with the following message, also in a signed datagram.  I
 {
     type: "CrawlerPong",
     version: 1,
+    clientVersion: "MuWire 1.2.3",
     peers: [ b64.1, b64.2...]
 }
 ```