diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusDriver.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusDriver.cs
index c045297d..c9163936 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusDriver.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ModbusDriver.cs
@@ -1491,30 +1491,13 @@ public sealed class ModbusDriver
     ///     Map a Modbus logical type to the driver-agnostic <see cref="DriverDataType"/> used
     ///     by the address-space builder.
     /// </summary>
-    /// <remarks>
-    ///     <para>
-    ///         <b>Driver.Modbus-007 — Int64 / UInt64 surfacing limitation:</b>
-    ///         <see cref="DriverDataType"/> does not yet include an Int64 enum member, so 64-bit
-    ///         Modbus tags currently surface as <see cref="DriverDataType.Int32"/> on the OPC UA
-    ///         address space. The wire codec (<c>DecodeRegister</c> / <c>EncodeRegister</c>) is
-    ///         correct — values round-trip as 64-bit <c>long</c> / <c>ulong</c> through
-    ///         <c>ReadAsync</c> / <c>WriteAsync</c>. Only the variable node's <c>DataType</c>
-    ///         attribute is misreported. Clients that consume the type advertisement will see a
-    ///         type/value mismatch for values outside the 32-bit signed range. Operators
-    ///         configuring <c>I_64</c> / <c>UI_64</c> tags should be aware of this until the
-    ///         tracked <c>DriverDataType.Int64</c> follow-up ships.
-    ///     </para>
-    /// </remarks>
-    private static DriverDataType MapDataType(ModbusDataType t) => t switch
+    internal static DriverDataType MapDataType(ModbusDataType t) => t switch
     {
         ModbusDataType.Bool or ModbusDataType.BitInRegister => DriverDataType.Boolean,
         ModbusDataType.Int16 or ModbusDataType.Int32 => DriverDataType.Int32,
         ModbusDataType.UInt16 or ModbusDataType.UInt32 => DriverDataType.Int32,
-        // Driver.Modbus-007: Int64 / UInt64 currently surface as Int32 because DriverDataType
-        // has no Int64 member yet. The wire codec preserves the 64-bit value; only the OPC UA
-        // node's declared DataType is widened. Tracked for a follow-up that adds the enum
-        // member + node-type advertisement.
-        ModbusDataType.Int64 or ModbusDataType.UInt64 => DriverDataType.Int32,
+        ModbusDataType.Int64 => DriverDataType.Int64,
+        ModbusDataType.UInt64 => DriverDataType.UInt64,
         ModbusDataType.Float32 => DriverDataType.Float32,
         ModbusDataType.Float64 => DriverDataType.Float64,
         ModbusDataType.String => DriverDataType.String,
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusDataTypeTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusDataTypeTests.cs
index e9b2a201..eea381c4 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusDataTypeTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ModbusDataTypeTests.cs
@@ -1,6 +1,7 @@
 using System.Buffers.Binary;
 using Shouldly;
 using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.Driver.Modbus;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests;
@@ -278,6 +279,17 @@ public sealed class ModbusDataTypeTests
         ModbusDriver.DecodeRegister(wire, lo).ShouldBe("eH");
     }
 
+    // --- MapDataType node DataType advertisement ---
+
+    /// <summary>
+    /// Verifies that 64-bit Modbus types surface the correct DriverDataType (not the stale Int32 fallback).
+    /// </summary>
+    [Theory]
+    [InlineData(ModbusDataType.Int64, DriverDataType.Int64)]
+    [InlineData(ModbusDataType.UInt64, DriverDataType.UInt64)]
+    public void MapDataType_64bit_surfaces_correct_DriverDataType(ModbusDataType wire, DriverDataType expected)
+        => ModbusDriver.MapDataType(wire).ShouldBe(expected);
+
     // --- BCD (binary-coded decimal, DL205/DL260 default numeric encoding) ---
 
     /// <summary>