diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index f739bdd..143baeb 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -76248,6 +76248,9 @@
 </histogram>
 
 <histogram name="Network.Shill.Wifi.ApMode" enum="WiFiApMode">
+  <obsolete>
+    Deprecated as of 05/2019.
+  </obsolete>
   <owner>kirtika@chromium.org</owner>
   <summary>
     Chrome OS network usage metric. The AP mode setting for each successful WiFi