diff --git a/RpcNep5Tracker/Nep5Balance.cs b/RpcNep5Tracker/Nep5Balance.cs
index efdfa04df..304028d08 100644
--- a/RpcNep5Tracker/Nep5Balance.cs
+++ b/RpcNep5Tracker/Nep5Balance.cs
@@ -10,18 +10,20 @@ public class Nep5Balance : StateBase, ICloneable<Nep5Balance>
         public BigInteger Balance;
         public uint LastUpdatedBlock;
 
-        public override int Size => base.Size + Balance.ToByteArray().GetVarSize();
+        public override int Size => base.Size + Balance.ToByteArray().GetVarSize() + sizeof(uint);
 
         public override void Serialize(BinaryWriter writer)
         {
             base.Serialize(writer);
             writer.WriteVarBytes(Balance.ToByteArray());
+            writer.Write(LastUpdatedBlock);
         }
 
         public override void Deserialize(BinaryReader reader)
         {
             base.Deserialize(reader);
             Balance = new BigInteger(reader.ReadVarBytes(512));
+            LastUpdatedBlock = reader.ReadUInt32();
         }
 
         public Nep5Balance Clone()
diff --git a/RpcNep5Tracker/Nep5BalanceKey.cs b/RpcNep5Tracker/Nep5BalanceKey.cs
index 0af045c97..b4a1710cf 100644
--- a/RpcNep5Tracker/Nep5BalanceKey.cs
+++ b/RpcNep5Tracker/Nep5BalanceKey.cs
@@ -9,6 +9,8 @@ public class Nep5BalanceKey : IComparable<Nep5BalanceKey>, IEquatable<Nep5Balanc
         public readonly UInt160 UserScriptHash;
         public readonly UInt160 AssetScriptHash;
 
+        public int Size => 20 + 20;
+
         public Nep5BalanceKey() : this(new UInt160(), new UInt160())
         {
         }
@@ -63,7 +65,5 @@ public void Deserialize(BinaryReader reader)
             ((ISerializable) UserScriptHash).Deserialize(reader);
             ((ISerializable) AssetScriptHash).Deserialize(reader);
         }
-
-        public int Size { get; } = 20 + 20;
     }
 }
\ No newline at end of file
diff --git a/RpcNep5Tracker/Nep5Transfer.cs b/RpcNep5Tracker/Nep5Transfer.cs
index df012634e..7ddf8c54a 100644
--- a/RpcNep5Tracker/Nep5Transfer.cs
+++ b/RpcNep5Tracker/Nep5Transfer.cs
@@ -2,7 +2,6 @@
 using System.Numerics;
 using Neo.IO;
 using Neo.Ledger;
-using Neo.Network.P2P.Payloads;
 
 namespace Neo.Plugins
 {
@@ -13,7 +12,7 @@ public class Nep5Transfer : StateBase, ICloneable<Nep5Transfer>
         public UInt256 TxHash;
         public BigInteger Amount;
 
-        public override int Size => base.Size + 20 + Amount.ToByteArray().GetVarSize();
+        public override int Size => base.Size + 20 + sizeof(uint) + 32 + Amount.ToByteArray().GetVarSize();
 
         public override void Serialize(BinaryWriter writer)
         {
diff --git a/RpcNep5Tracker/Nep5TransferKey.cs b/RpcNep5Tracker/Nep5TransferKey.cs
index 3df0af23e..a1892d54a 100644
--- a/RpcNep5Tracker/Nep5TransferKey.cs
+++ b/RpcNep5Tracker/Nep5TransferKey.cs
@@ -11,6 +11,8 @@ public class Nep5TransferKey : IComparable<Nep5TransferKey>, IEquatable<Nep5Tran
         public readonly UInt160 AssetScriptHash;
         public ushort BlockXferNotificationIndex { get; private set; }
 
+        public int Size => 20 + sizeof(uint) + 20 + sizeof(ushort);
+
         public Nep5TransferKey() : this(new UInt160(), 0, new UInt160(), 0)
         {
         }
@@ -76,15 +78,13 @@ public void Serialize(BinaryWriter writer)
 
         public void Deserialize(BinaryReader reader)
         {
-            ((ISerializable) UserScriptHash).Deserialize(reader);
+            ((ISerializable)UserScriptHash).Deserialize(reader);
             byte[] timestampBytes = new byte[sizeof(uint)];
             reader.Read(timestampBytes, 0, sizeof(uint));
             if (BitConverter.IsLittleEndian) Array.Reverse(timestampBytes);
             Timestamp = BitConverter.ToUInt32(timestampBytes, 0);
-            ((ISerializable) AssetScriptHash).Deserialize(reader);
+            ((ISerializable)AssetScriptHash).Deserialize(reader);
             BlockXferNotificationIndex = reader.ReadUInt16();
         }
-
-        public int Size { get; } = 20 + sizeof(byte) + sizeof(uint) + 20 + sizeof(ushort);
     }
 }
\ No newline at end of file