diff --git a/common/constants.cc b/common/constants.cc
index 8883668..a9cf238 100644
--- a/common/constants.cc
+++ b/common/constants.cc
@@ -71,6 +71,7 @@
 const char kPrefsPingActive[] = "active";
 const char kPrefsPingLastActive[] = "date_last_active";
 const char kPrefsPingLastRollcall[] = "date_last_rollcall";
+const char kPrefsLastFp[] = "last-fp";
 const char kPrefsPostInstallSucceeded[] = "post-install-succeeded";
 const char kPrefsPreviousVersion[] = "previous-version";
 const char kPrefsResumedUpdateFailures[] = "resumed-update-failures";