Likely due to the cost of supporting end-of-life operating systems.

You can look at vendors that offer their own .NET libraries for COM access.

During development, we got a windows virtual machine that runs the OPC DA server. Using OPC Expert, we can already see the server and read variable changes. 

So far so good, but how can we implement a client that can read the data?

What we tried so far: 

a) python 32bit with pywin32 and OpenOPC

b) Native .net 8 

Both won't work because the automation layer (opcdaauto.dll from OPC Foundation) is not present.

What is the official way to develop a client, and from where do we get the opcdaauto.dll since it is not bundled in the redistributable package download?

Thanks in advance!

Are you available to verify before it is posted?

The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2753. The arguments are: file_OpcEnum.E25DF0F2_0F29_47E8_8537_265285ED9757, ,

Error code 2753 is "The File '[2]' is not marked for installation."

There is a similar issue with UnregisterOpcEnum.E25DF0F2_0F29_47E8_8537_265285ED9757 action which doesn't handle uninstalling an optional feature that includes the merge module without uninstalling the whole application.

A possible fix is to change the register condition to: $comp_OpcEnum.E25DF0F2_0F29_47E8_8537_265285ED9757 = 3

and the unregister condition to: $comp_OpcEnum.E25DF0F2_0F29_47E8_8537_265285ED9757 = 2

which takes into account the action being performed to the OpcEnum component.

The same problem exists in the "opc-com-proxystub-mergemodule-3.1.1-x64.msm" merge module with the RegisterOpcCategoryManager.E68AB89F_6DF7_4750_8BC1_F14B2064F313 and UnregisterOpcCategoryManager.E68AB89F_6DF7_4750_8BC1_F14B2064F313 actions.

Fix for register condition: $comp_OpcCategoryManager.E68AB89F_6DF7_4750_8BC1_F14B2064F313 = 3

Fix for unregister condition: $comp_OpcCategoryManager.E68AB89F_6DF7_4750_8BC1_F14B2064F313 = 2

Specifically the component GUID's in "opc-com-proxystub-mergemodule-3.1.1-x86.msm" and "opc-com-proxystub-mergemodule-3.1.1-x64.msm" are the same. Similarly, the GUIDs in "opc-com-sdk-mergemodule-3.1.1-x86.msm" and "opc-com-sdk-mergemodule-3.1.1-x64.msm" are also the same.

This issue can be seen by validating "opc-core-components-redistributable-3.1.1-x64.msi" using Microsoft Orca (see https://learn.microsoft.com/en.....i/orca-exe). It also occurs in any product that includes both x86 and x64 merge modules in it's MSI file.

ICE08 ERROR Component: comp_opcsec_ps.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0008-4000-8000-000000000008}
ICE08 ERROR Component: comp_opchda_ps.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0007-4000-8000-000000000007}
ICE08 ERROR Component: comp_OpcDxPs.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0006-4000-8000-000000000006}
ICE08 ERROR Component: comp_OpcCmdPs.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0005-4000-8000-000000000005}
ICE08 ERROR Component: comp_opcbc_ps.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0004-4000-8000-000000000004}
ICE08 ERROR Component: comp_opc_aeps.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0003-4000-8000-000000000003}
ICE08 ERROR Component: comp_opcproxy.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0002-4000-8000-000000000002}
ICE08 ERROR Component: comp_opccomn_ps.E68AB89F_6DF7_4750_8BC1_F14B2064F313 has a duplicate GUID: {A1B2C3D4-0001-4000-8000-000000000001}

ICE08 ERROR Component: sdk_OpcDxError_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-001A-4000-9000-00000000001A}
ICE08 ERROR Component: sdk_OpcDx_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0019-4000-9000-000000000019}
ICE08 ERROR Component: sdk_OpcDx_i.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0018-4000-9000-000000000018}
ICE08 ERROR Component: sdk_OpcDx_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0017-4000-9000-000000000017}
ICE08 ERROR Component: sdk_OpcCmdError_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0016-4000-9000-000000000016}
ICE08 ERROR Component: sdk_OpcCmd_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0015-4000-9000-000000000015}
ICE08 ERROR Component: sdk_OpcCmd_i.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0014-4000-9000-000000000014}
ICE08 ERROR Component: sdk_OpcCmd_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0013-4000-9000-000000000013}
ICE08 ERROR Component: sdk_OpcBatchDef_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0012-4000-9000-000000000012}
ICE08 ERROR Component: sdk_OpcBatchProps_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0011-4000-9000-000000000011}
ICE08 ERROR Component: sdk_OpcBatchError_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0010-4000-9000-000000000010}
ICE08 ERROR Component: sdk_opcbc_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-000F-4000-9000-00000000000F}
ICE08 ERROR Component: sdk_OpcCmdPs_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0034-4000-9000-000000000034}
ICE08 ERROR Component: sdk_opcsec_ps_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0037-4000-9000-000000000037}
ICE08 ERROR Component: sdk_opchda_ps_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0036-4000-9000-000000000036}
ICE08 ERROR Component: sdk_opcbc_ps_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0033-4000-9000-000000000033}
ICE08 ERROR Component: sdk_OpcDxPs_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0035-4000-9000-000000000035}
ICE08 ERROR Component: sdk_opchda_i.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-001C-4000-9000-00000000001C}
ICE08 ERROR Component: sdk_opc_aeps_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0032-4000-9000-000000000032}
ICE08 ERROR Component: sdk_opcproxy_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0031-4000-9000-000000000031}
ICE08 ERROR Component: sdk_opccomn_ps_dll.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0030-4000-9000-000000000030}
ICE08 ERROR Component: sdk_OpcErrSec_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0022-4000-9000-000000000022}
ICE08 ERROR Component: sdk_opcSec_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0021-4000-9000-000000000021}
ICE08 ERROR Component: sdk_opcSec_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-001F-4000-9000-00000000001F}
ICE08 ERROR Component: sdk_opcSec_i.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0020-4000-9000-000000000020}
ICE08 ERROR Component: sdk_OpcHda_Error_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-001E-4000-9000-00000000001E}
ICE08 ERROR Component: sdk_opchda_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-001D-4000-9000-00000000001D}
ICE08 ERROR Component: sdk_opchda_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-001B-4000-9000-00000000001B}
ICE08 ERROR Component: sdk_opcbc_i.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-000E-4000-9000-00000000000E}
ICE08 ERROR Component: sdk_opcbc_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-000D-4000-9000-00000000000D}
ICE08 ERROR Component: sdk_opcaedef_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-000C-4000-9000-00000000000C}
ICE08 ERROR Component: sdk_opcae_er_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-000B-4000-9000-00000000000B}
ICE08 ERROR Component: sdk_opc_ae_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-000A-4000-9000-00000000000A}
ICE08 ERROR Component: sdk_opc_ae_i.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0009-4000-9000-000000000009}
ICE08 ERROR Component: sdk_opc_ae_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0008-4000-9000-000000000008}
ICE08 ERROR Component: sdk_opcerror_h.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0007-4000-9000-000000000007}
ICE08 ERROR Component: sdk_opcda_idl.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0006-4000-9000-000000000006}
ICE08 ERROR Component: sdk_opcda_i.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0005-4000-9000-000000000005}
ICE08 ERROR Component: sdk_opcda_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0004-4000-9000-000000000004}
ICE08 ERROR Component: sdk_opccomn_idl.E68AB8A0_6DF7_4750_8BC1_F14B2064F314 has a duplicate GUID: {B2C3D4E5-0003-4000-9000-000000000003}
ICE08 ERROR Component: sdk_opccomn_i.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0002-4000-9000-000000000002}
ICE08 ERROR Component: sdk_opccomn_h.E25DF0F3_0F29_47E8_8537_265285ED9758 has a duplicate GUID: {B2C3D4E5-0001-4000-9000-000000000001}

These GUID appear to have been created 'manually' rather the usual algorithmically generated unique GUID's.

The installer is using a new tool but it should be backward compatible.

It should be a drop in replacement for the existing installers/merge modules but we have not tested every permutation of system.

If bugs exist they will be fixed.

using System;
using Opc;
using Opc.Da;

namespace OpcClientSimple
{
class Program
{
static void Main(string[] args)
{
// 1. Define the Server URL (Local or Remote)
// Format: opcda://[Hostname]/[ProgID]
string url = "opcda://localhost/Matrikon.OPC.Simulation.1";

Opc.IDiscovery discovery = new OpcCom.ServerEnumerator();
Opc.Server server = new Opc.Da.Server(new OpcCom.Factory(), null);

try
{
// 2. Connect to the Server
server.Url = new Opc.URL(url);
server.Connect();
Console.WriteLine("Connected to: " + server.Url);

// 3. Create a Group (Subscription)
SubscriptionState state = new SubscriptionState();
state.Name = "MyGroup";
state.Active = true;

Subscription subscription = (Subscription)server.CreateSubscription(state);

// 4. Add Items (Tags) to the Group
Item[] items = new Item[1];
items[0] = new Item(new ItemIdentifier("Random.Int4"));

items = subscription.AddItems(items);

// 5. Synchronous Read
ItemValueResult[] results = subscription.Read(subscription.Items);

foreach (ItemValueResult result in results)
{
Console.WriteLine($"Item: {result.ItemName} | Value: {result.Value} | Quality: {result.Quality}");
}

// 6. Cleanup
server.Disconnect();
}
catch (Exception ex)
{
Console.WriteLine("Error: " + ex.Message);
}
}
}
}..

If you change your OS you will need new drivers for whatever h/w you have no matter what API is provided.

If you have a h/w that is only supported on windows then you will have bigger issues than OPC compatibility.

If your h/w has a lower level API that does work on Linux then your best best is to write a UA server that uses this lower level API.

netstandard2.1;netstandard2.0;net46

https://opcfoundation.org/deve.....-packages/

If all of your OPC apps use later versions of .NET you should be able to safely delete opcrcw.* 

There is a need to update the OPC Foundation .net DLLs to remove the dependency on deprecated .NET versions that potentially increase the risk of vulnerability from a cyber security aspect.

These are the .dlls our Cyber team are finding delivered that are showing dependencies on deprecated .NET versions:

FileName Dependency (mscorlib/.net version)
opcnetapi.com.dll v2.0
opcnetapi.dll v2.0
opcnetapi.xml.dll v2.0
opcrcw.ae.dll v1.0.5000.0
opcrcw.batch.dll v1.0.5000.0
opcrcw.cmd.dll v1.0.5000.0
opcrcw.comn.dll v1.0.5000.0
opcrcw.da.dll v1.0.5000.0
opcrcw.dx.dll v1.0.5000.0
opcrcw.hda.dll v1.0.5000.0
opcrcw.sec.dll v1.0.5000.0