diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/NamespaceMap.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/NamespaceMap.cs
similarity index 99%
rename from src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/NamespaceMap.cs
rename to src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/NamespaceMap.cs
index f583bf65..82ab003f 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/NamespaceMap.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/NamespaceMap.cs
@@ -32,7 +32,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
 ///         direct parse against the current session.
 ///     </para>
 /// </remarks>
-internal sealed class NamespaceMap
+public sealed class NamespaceMap
 {
     // index -> URI and URI -> index, as the upstream server published them at connect time.
     private readonly string[] _uris;
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts.csproj b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts.csproj
index 3896f7bd..8e2c9fac 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts.csproj
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts.csproj
@@ -5,5 +5,7 @@
         <ImplicitUsings>enable</ImplicitUsings>
         <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     </PropertyGroup>
-    <!-- NO PackageReference. NO ProjectReference. -->
+    <ItemGroup>
+        <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua.Client" />
+    </ItemGroup>
 </Project>