diff --git a/index.bs b/index.bs
index 92adf7edf..2448cd35d 100644
--- a/index.bs
+++ b/index.bs
@@ -4,6 +4,7 @@ Status: ED
 Prepare for TR: true
 TR: https://www.w3.org/TR/webauthn/
 ED: https://w3c.github.io/webauthn/
+Previous Version: http://www.w3.org/TR/2017/WD-webauthn-20170505/
 Previous Version: https://www.w3.org/TR/2017/WD-webauthn-20170216/
 Previous Version: https://www.w3.org/TR/2016/WD-webauthn-20161207/
 Previous Version: https://www.w3.org/TR/2016/WD-webauthn-20160928/