diff --git a/constants.cc b/constants.cc
index 0f425d7..e4aa199 100644
--- a/constants.cc
+++ b/constants.cc
@@ -34,6 +34,7 @@
 const char kPrefsPayloadAttemptNumber[] = "payload-attempt-number";
 const char kPrefsPreviousVersion[] = "previous-version";
 const char kPrefsResumedUpdateFailures[] = "resumed-update-failures";
+const char kPrefsSystemUpdatedMarker[] = "system-updated-marker";
 const char kPrefsTotalBytesDownloaded[] = "total-bytes-downloaded";
 const char kPrefsUpdateCheckCount[] = "update-check-count";
 const char kPrefsUpdateCheckResponseHash[] = "update-check-response-hash";