diff --git a/common/constants.cc b/common/constants.cc
index 88d0445..c0a6e27 100644
--- a/common/constants.cc
+++ b/common/constants.cc
@@ -78,6 +78,7 @@
 const char kPrefsUpdateStateNextDataLength[] = "update-state-next-data-length";
 const char kPrefsUpdateStateNextDataOffset[] = "update-state-next-data-offset";
 const char kPrefsUpdateStateNextOperation[] = "update-state-next-operation";
+const char kPrefsUpdateStatePayloadIndex[] = "update-state-payload-index";
 const char kPrefsUpdateStateSHA256Context[] = "update-state-sha-256-context";
 const char kPrefsUpdateStateSignatureBlob[] = "update-state-signature-blob";
 const char kPrefsUpdateStateSignedSHA256Context[] =