diff --git a/src/LedgerFormats.cpp b/src/LedgerFormats.cpp
index 58507b6d9d..c7383016b2 100644
--- a/src/LedgerFormats.cpp
+++ b/src/LedgerFormats.cpp
@@ -10,6 +10,8 @@ LedgerEntryFormat LedgerFormats[]=
 		{ S_FIELD(Sequence),			STI_UINT32,		SOE_REQUIRED, 0 },
 		{ S_FIELD(Balance),				STI_AMOUNT,		SOE_REQUIRED, 0 },
 		{ S_FIELD(LastReceive),			STI_UINT32,		SOE_REQUIRED, 0 },
+		{ S_FIELD(LastSignedSeq),		STI_UINT32,		SOE_REQUIRED, 0 },
+		{ S_FIELD(LastTxnID),			STI_HASH256,	SOE_REQUIRED, 0 },
 		{ S_FIELD(LastTxnSeq),			STI_UINT32,		SOE_REQUIRED, 0 },
 		{ S_FIELD(AuthorizedKey),		STI_ACCOUNT,	SOE_IFFLAG,   1 },
 		{ S_FIELD(EmailHash),			STI_HASH128,	SOE_IFFLAG,   2 },
@@ -52,6 +54,8 @@ LedgerEntryFormat LedgerFormats[]=
 		{ S_FIELD(BookDirectory),		STI_HASH256,	SOE_REQUIRED, 0 },
 		{ S_FIELD(BookNode),			STI_UINT64,		SOE_REQUIRED, 0 },
 		{ S_FIELD(OwnerNode),			STI_UINT64,		SOE_REQUIRED, 0 },
+		{ S_FIELD(LastTxnID),			STI_HASH256,	SOE_REQUIRED, 0 },
+		{ S_FIELD(LastTxnSeq),			STI_UINT32,		SOE_REQUIRED, 0 },
 		{ S_FIELD(PaysIssuer),			STI_ACCOUNT,	SOE_IFFLAG,   1 },
 		{ S_FIELD(GetsIssuer),			STI_ACCOUNT,	SOE_IFFLAG,   2 },
 		{ S_FIELD(Expiration),			STI_UINT32,		SOE_IFFLAG,   4 },
@@ -65,6 +69,8 @@ LedgerEntryFormat LedgerFormats[]=
 		{ S_FIELD(LowLimit),			STI_AMOUNT,		SOE_REQUIRED, 0 },
 		{ S_FIELD(HighID),				STI_ACCOUNT,	SOE_REQUIRED, 0 },
 		{ S_FIELD(HighLimit),			STI_AMOUNT,		SOE_REQUIRED, 0 },
+		{ S_FIELD(LastTxnID),			STI_HASH256,	SOE_REQUIRED, 0 },
+		{ S_FIELD(LastTxnSeq),			STI_UINT32,		SOE_REQUIRED, 0 },
 		{ S_FIELD(LowQualityIn),		STI_UINT32,		SOE_IFFLAG,   1 },
 		{ S_FIELD(LowQualityOut),		STI_UINT32,		SOE_IFFLAG,   2 },
 		{ S_FIELD(HighQualityIn),		STI_UINT32,		SOE_IFFLAG,   4 },
diff --git a/src/SerializedLedger.cpp b/src/SerializedLedger.cpp
index 3cc5c70dc0..e79b19c1b7 100644
--- a/src/SerializedLedger.cpp
+++ b/src/SerializedLedger.cpp
@@ -96,13 +96,17 @@ uint32 SerializedLedgerEntry::getThreadedLedger()
 	return getIFieldU32(sfLastTxnSeq);
 }
 
-void SerializedLedgerEntry::thread(const uint256& txID, uint32 ledgerSeq, uint256& prevTxID, uint32& prevLedgerID)
+bool SerializedLedgerEntry::thread(const uint256& txID, uint32 ledgerSeq, uint256& prevTxID, uint32& prevLedgerID)
 {
-	prevTxID = getIFieldH256(sfLastTxnID);
+	uint256 oldPrevTxID = getIFieldH256(sfLastTxnID);
+	if (oldPrevTxID == txID)
+		return false;
+	prevTxID = oldPrevTxID;
 	prevLedgerID = getIFieldU32(sfLastTxnID);
 	assert(prevTxID != txID);
 	setIFieldH256(sfLastTxnID, txID);
 	setIFieldU32(sfLastTxnSeq, ledgerSeq);
+	return true;
 }
 
 std::vector<uint256> SerializedLedgerEntry::getOwners()
diff --git a/src/SerializedLedger.h b/src/SerializedLedger.h
index c8ac2d96e5..5f66a765dc 100644
--- a/src/SerializedLedger.h
+++ b/src/SerializedLedger.h
@@ -67,7 +67,7 @@ public:
 	bool isThreaded();		// is this ledger entry actually threaded
 	uint256 getThreadedTransaction();
 	uint32 getThreadedLedger();
-	void thread(const uint256& txID, uint32 ledgerSeq, uint256& prevTxID, uint32& prevLedgerID);
+	bool thread(const uint256& txID, uint32 ledgerSeq, uint256& prevTxID, uint32& prevLedgerID);
 	std::vector<uint256> getOwners();	// nodes notified if this node is deleted
 
 	void setIFieldU8(SOE_Field field, unsigned char v) { return mObject.setValueFieldU8(field, v); }
diff --git a/src/SerializedObject.h b/src/SerializedObject.h
index 5453a987b7..8ee7a6b4c8 100644
--- a/src/SerializedObject.h
+++ b/src/SerializedObject.h
@@ -63,6 +63,7 @@ enum SOE_Field
 	sfInvoiceID,
 	sfLastNode,
 	sfLastReceive,
+	sfLastSignedSeq,
 	sfLastTxnID,
 	sfLastTxnSeq,
 	sfLedgerHash,
diff --git a/src/TransactionEngine.cpp b/src/TransactionEngine.cpp
index 583f287653..d877c0ffd4 100644
--- a/src/TransactionEngine.cpp
+++ b/src/TransactionEngine.cpp
@@ -1219,6 +1219,7 @@ TransactionEngineResult TransactionEngine::applyTransaction(const SerializedTran
 			terResult	= terPAST_SEQ;
 		}
 	}
+	mTxnAccount->setIFieldU32(sfLastSignedSeq, mLedger->getLedgerSeq());
 
 	if (terSUCCESS == terResult)
 	{
diff --git a/src/Version.h b/src/Version.h
index 51603753c5..957327c2a0 100644
--- a/src/Version.h
+++ b/src/Version.h
@@ -16,11 +16,11 @@
 
 // Version we prefer to speak:
 #define PROTO_VERSION_MAJOR			0
-#define PROTO_VERSION_MINOR			4
+#define PROTO_VERSION_MINOR			5
 
 // Version we wil speak to:
 #define MIN_PROTO_MAJOR				0
-#define MIN_PROTO_MINOR				4
+#define MIN_PROTO_MINOR				5
 
 #define MAKE_VERSION_INT(maj,min)	((maj << 16) | min)
 #define GET_VERSION_MAJOR(ver)		(ver >> 16)