diff --git a/CHANGES.md b/CHANGES.md
index c06bb5bc2d9..98c9042b20f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -42,6 +42,10 @@ be compatible with this version,  specifically, those that ran with
  -  (Libplanet.Store) Added `FullNode.RemoveChild()` method.  [[#3576]]
  -  (Libplanet.Action) Added `IAccount.RemoveState()` interface method.
     [[#3577]]
+ -  (Libplanet.Explorer) Added `LegacyBencodexValueType` class that is
+    a copy of an old `BencodexValueType` with its name changed
+    for backwards compatibility.  Changed old `states` query
+    to use `LegacyBencodexValueType` instead of `BencodexValueType`.  [[#3579]]
 
 [#3559]: https://github.com/planetarium/libplanet/pull/3559
 [#3560]: https://github.com/planetarium/libplanet/pull/3560
@@ -54,6 +58,7 @@ be compatible with this version,  specifically, those that ran with
 [#3574]: https://github.com/planetarium/libplanet/pull/3574
 [#3576]: https://github.com/planetarium/libplanet/pull/3576
 [#3577]: https://github.com/planetarium/libplanet/pull/3577
+[#3579]: https://github.com/planetarium/libplanet/pull/3579
 
 
 Version 3.9.2
diff --git a/Libplanet.Explorer.Tests/Queries/StateQueryTest.cs b/Libplanet.Explorer.Tests/Queries/StateQueryTest.cs
index f820cab6bbf..fe1e2fad5ef 100644
--- a/Libplanet.Explorer.Tests/Queries/StateQueryTest.cs
+++ b/Libplanet.Explorer.Tests/Queries/StateQueryTest.cs
@@ -33,9 +33,7 @@ public async Task States()
                  addresses: [""0x5003712B63baAB98094aD678EA2B24BcE445D076"", ""0x0000000000000000000000000000000000000000""],
                  offsetBlockHash:
                      ""01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b""
-            ) {
-                hex
-            }
+            )
         }
         ", source: source);
         Assert.Null(result.Errors);
@@ -45,14 +43,7 @@ public async Task States()
         object[] states =
             Assert.IsAssignableFrom<object[]>(resultDict["states"]);
         Assert.Equal(2, states.Length);
-        Assert.Equal(
-            new Dictionary<string, object>()
-            {
-                { "hex", "6e" },
-            },
-            Assert.IsAssignableFrom<IDictionary<string, object>>(states[0])
-        );
-        Assert.Null(states[1]);
+        Assert.Equal(new[] { new byte[] { 110, }, null }, states);
     }
 
     [Fact]
@@ -186,9 +177,7 @@ public async Task ThrowExecutionErrorIfViolateMutualExclusive()
                      ""01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b"",
                  offsetStateRootHash:
                      ""c33b27773104f75ac9df5b0533854108bd498fab31e5236b6f1e1f6404d5ef64""
-            ) {
-                hex
-            }
+            )
         }
         ", source: source);
         Assert.IsType<ExecutionErrors>(result.Errors);
@@ -205,9 +194,7 @@ public async Task StatesBySrh()
                  addresses: [""0x5003712B63baAB98094aD678EA2B24BcE445D076"", ""0x0000000000000000000000000000000000000000""],
                  offsetStateRootHash:
                      ""c33b27773104f75ac9df5b0533854108bd498fab31e5236b6f1e1f6404d5ef64""
-            ) {
-                hex
-            }
+            )
         }
         ", source: source);
         Assert.Null(result.Errors);
@@ -216,15 +203,7 @@ public async Task StatesBySrh()
             Assert.IsAssignableFrom<IDictionary<string, object>>(resultData!.ToValue());
         object[] states =
             Assert.IsAssignableFrom<object[]>(resultDict["states"]);
-        Assert.Equal(2, states.Length);
-        Assert.Equal(
-            new Dictionary<string, object>()
-            {
-                { "hex", "6e" },
-            },
-            Assert.IsAssignableFrom<IDictionary<string, object>>(states[0])
-        );
-        Assert.Null(states[1]);
+        Assert.Equal(new[] { new byte[] { 110, }, null }, states);
     }
 
     [Fact]
diff --git a/Libplanet.Explorer/GraphTypes/LegacyBencodexValueType.cs b/Libplanet.Explorer/GraphTypes/LegacyBencodexValueType.cs
new file mode 100644
index 00000000000..8e10ed415ce
--- /dev/null
+++ b/Libplanet.Explorer/GraphTypes/LegacyBencodexValueType.cs
@@ -0,0 +1,51 @@
+using System;
+using Bencodex;
+using GraphQL.Language.AST;
+using GraphQL.Types;
+using Libplanet.Common;
+
+namespace Libplanet.Explorer.GraphTypes
+{
+    public class LegacyBencodexValueType : StringGraphType
+    {
+        private static readonly Codec _codec = new();
+
+        public LegacyBencodexValueType()
+        {
+            Name = "LegacyBencodexValue";
+        }
+
+        public override object? Serialize(object? value)
+        {
+            if (value is Bencodex.Types.IValue iv)
+            {
+                return _codec.Encode(iv);
+            }
+
+            return value;
+        }
+
+        public override object? ParseValue(object? value)
+        {
+            return value switch
+            {
+                null => null,
+                string hex => _codec.Decode(ByteUtil.ParseHex(hex)),
+                _ => throw new ArgumentException(
+                    $"Expected a hexadecimal string but {value}",
+                    nameof(value)
+                ),
+            };
+        }
+
+        public override object? ParseLiteral(IValue? value)
+        {
+            if (value is StringValue)
+            {
+                return ParseValue(value.Value);
+            }
+
+            return null;
+        }
+    }
+}
diff --git a/Libplanet.Explorer/Queries/StateQuery.cs b/Libplanet.Explorer/Queries/StateQuery.cs
index 353a29d1f0a..962145f6261 100644
--- a/Libplanet.Explorer/Queries/StateQuery.cs
+++ b/Libplanet.Explorer/Queries/StateQuery.cs
@@ -15,7 +15,7 @@ public class StateQuery : ObjectGraphType<IBlockChainStates>
     public StateQuery()
     {
         Name = "StateQuery";
-        Field<NonNullGraphType<ListGraphType<BencodexValueType>>>(
+        Field<NonNullGraphType<ListGraphType<LegacyBencodexValueType>>>(
             "states",
             arguments: new QueryArguments(
                 new QueryArgument<NonNullGraphType<ListGraphType<NonNullGraphType<AddressType>>>>