Closes #4479 The CTT skipped a number of reference-server test cases because the sample address space, the diagnostics EnabledFlag or the CTT project settings did not provide what the scripts need. This PR fixes the sample data and the server behaviour behind those skips, updates `samples/UAReferenceServer.ctt.xml`, and records the CTT script defects that the newly running cases expose. ## Changes ### Sample address space (`ReferenceServer.NodeSet2.xml`, `ReferenceNodeManager`) | # | Skip | Fix | | --- | --- | --- | | 1 | Base Info Engineering Units `004.js`: ArrayItemType `EngineeringUnits` have an empty NamespaceUri | UNECE `mV` (12890) EUInformation, and the axis definitions use `s` (5457219) instead of UnitId 0. | | 2 | Data Access PercentDeadband `006/016/017`: `DataAccess_AnalogType_Float` EURange 0..0 | EURange 0..100 like the other analog items. | | 3 | Attribute Read `033.js` (19 nodes): second dimension of 3 | All `Scalar_Static_Arrays2D_*` are 5x5 (generated values; the Variant matrix holds scalar Int32 elements). The code-seeded Integer/Number/UInteger matrices are 5x5 too. | | 4 | View Minimum Continuation Point 01 `012.js`, View Basic 2 `018.js`: Method/View nodes need two references of their own NodeClass | `Methods_Void` HasCause/HasEffect to two methods, `Views_Operations` HasCause/HasEffect to `Views_Engineering`. | | 5 | Base Info Server Capabilities 2 `002.js`: no node without MinimumSamplingInterval | `DataAccess_DataItem_String` reports `Bad_AttributeIdInvalid` for the optional attribute (Part 3 §5.6.2). A DA item is used because Address Space WriteMask writes every attribute of the static scalars back. | | 6 | Historical Access Read Raw `Err-025.js`: no non-historizing Static Scalar | New `Scalar_Static_NonHistorizing_Boolean` (HistoryRead access, Historizing = false). See the historian change below. | | 10 | Address Space Atomicity `001.js`: no NonatomicRead node found | New `AccessRights_AccessAll_NonatomicReadWrite`. The script examines only the first 10000 variables sorted by NodeId string; the 5000 mass variables sort before `Scalar_Static_NonatomicReadWrite`. | ### Server library - **Diagnostics EnabledFlag (item 7, Base Info Diagnostics `018-1/2/3`).** `Server.ServerDiagnostics.EnabledFlag` is writable for SecurityAdmin or ConfigureAdmin over SignAndEncrypt (UserAccessLevel hook, asynchronous write handler); other users get `Bad_UserAccessDenied`. Transitions are serialized, including the node removal. Disabling returns `Bad_NotReadable` for ServerDiagnosticsSummary, its children and the diagnostics arrays, and removes the session and subscription diagnostics nodes (Part 5 §6.3.3). The server keeps the registrations: enabling restores the nodes of the live sessions and subscriptions with the same NodeIds (sessions created while disabled included) and resets the arrays to Good. Counters stay cumulative (required by `018-1.js`). Subscriptions created while diagnostics are disabled still get no diagnostics node. - `DiagnosticsNodeManager.IsDiagnosticsStructureNode` had an inverted NodeId check, so monitored diagnostics nodes never started the scan timer; `OnMonitoringModeChangedAsync` counted every node and replaced a running timer. Both fixed. - **Non-historized nodes (item 6).** `HistorianDispatcher` raw/modified, processed and at-time reads ask the resolved provider `IsHistorizingAsync` and return `Bad_HistoryOperationUnsupported` for a node it does not historize, instead of the empty result the in-memory historian gave for any node. - **Browse order (item 8).** `ReferenceDictionary.Find` returned references of a type from hash-based target maps, so a Browse filtered by ReferenceType returned references in a different order than an unfiltered Browse. It now returns them in insertion order (no extra allocation; a single match keeps the fast path). View Basic 2 `015.js` compares both lists by index. The characterization test in `NodeStateReferenceStorageTests` is updated accordingly. ### CTT project settings (`samples/UAReferenceServer.ctt.xml`) | Setting | Old | New | | --- | --- | --- | | `/Server Test/NodeIds/Static/All Profiles/Scalar/Bool` | `ns=2;s=Scalar_Static_Boolean` | `ns=2;s=Scalar_Static_NonHistorizing_Boolean` | | `/Server Test/NodeIds/References/Has References of a ReferenceType and SubType` | `ns=2;s=References_HasReferenceTypeAndSubType` | `i=2253` | | `/Server Test/NodeIds/NodeClasses/Object` | `ns=2;s=Scalar` | `i=2253` | `References_HasReferenceTypeAndSubType` loses its HasComponent/HasOrderedComponent references in the source generator; that is tracked in #4484 and not changed here. The Server object has HasComponent and HasAddIn references. ### Decisions - **Item 11, Attribute Write StatusCode & Timestamp `003/006/008` (writing ServerTimestamp): unchanged.** The stack rejects writes that contain a ServerTimestamp (`NodeState`/`BaseVariableState`), which Part 4 §5.11.4.2 allows (`Bad_WriteNotSupported`); the CTT reports it as "Not Supported", not as an error. Side finding, not changed: the StatusWrite/TimestampWrite AccessLevel bits are not enforced. - **Item 6:** Part 4 §5.11.3.4 (Table 52) specifies `Bad_HistoryOperationUnsupported`; `Err-025.js` accepts only `Bad_NotSupported`, so the case now runs and reports that as an error. Recorded as a CTT defect in `plans/ctt-issues.md`. - **Item 12:** removed the stale Historical Access `Err-012.js` entry (fixed by #4026). `plans/ctt-issues.md` adds C32 (`Err-025.js` status code), C33 (Atomicity `001.js`: 10000 cap, operator precedence, substring matching of `UaNodesToIgnore`) and C34 (View Basic 2 `015.js` index comparison), and replaces the Err-025/Err-012 configuration notes with the new settings and the EnabledFlag access requirement. Monitor Basic `039.js` is already C17. The run procedure in `plans/ctt-testing.md` is unchanged. ## Verification CTT 1.05.06, scripts 1.05.513, `ConsoleReferenceServer --ctt -a`, fresh server per conformance unit/group. "master" =5362ec5e5with the unchanged project settings. **Targeted CUs (skips before → after):** Attribute Read `033` Pass; Base Info Diagnostics `018-2`, `018-3` Pass, `018-1` Warning (*"Session diagnostics not available"* for the session the script creates while diagnostics are disabled); Base Info Engineering Units `001` Inconclusive→Pass, `004` Pass; Base Info Server Capabilities 2 `002` Pass; Data Access PercentDeadband `016`, `017` Warning→Pass; View Basic 2 `005`, `015`, `016`, `018`, `020` Pass; View Minimum Continuation Point 01 `010`, `011` Pass, `012` Warning→Pass; Address Space Atomicity `001` Pass; Monitor Value Change V2 `042` Error→Pass; Historical Access Read Raw `Err-025` runs (CTT status-code defect above); `013` fails on a varying number of results per run (1–12, also 11 on master), the documented continuation-point defect #16. Unchanged: Monitor Basic `039` (CTT script error), Monitor Value Change V2 `020` skip (`Arrays/ByteString` elements shorter than 4 bytes, not part of #4479), Historical Access Delete Value all pass. **Saved selection (1,882 cases) per group, errors:** Address Space Model 0 → 0, Aggregates 4558 → 4558 and Base Information 19 → 19 (identical messages) measured master (5362ec5e5) → this PR; after merging master (#4478) and the review fixes, Aggregates 4210 and Base Information 19; Attribute Services, Base Services, Data Access, Method Services and View Services 0 errors with this PR (0 in the recorded baseline). **Tests** (net10.0): Opc.Ua.Types.Tests 10395 passed, Opc.Ua.Server.Tests 5561 passed, Opc.Ua.InformationModel.Tests 1082 passed, Opc.Ua.History.Tests 519 passed, Opc.Ua.Client.Tests 2266 passed; no failures. New regression tests: `ReferenceServerTests` (units/ranges, 5x5 matrices, missing MinimumSamplingInterval, non-historizing HistoryRead, NodeClass references, Server object reference subtypes, both nonatomic nodes), `DiagnosticsNodeManagerTests.SetDiagnosticsEnabledAsync_Toggle_HidesAndRestoresDiagnosticsAsync`, `BaseInfoEnabledFlagToggleTests` (admin-only write, Bad_NotReadable while disabled, restore after enable), `ReferenceTableTests.FindReturnsReferencesInInsertionOrder`. 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Opus 5 <noreply@anthropic.com> Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
OPC UA .NET Standard Stack
🆕 This is version 2.0 of the OPC UA .NET Standard Stack (current
master).Looking for the supported 1.x release? It lives on the
master378branch (last release:1.5.378). All new feature work happens here onmaster;master378continues to receive security and critical-bug fixes for the 1.x line.
The official OPC Foundation reference implementation of OPC UA for .NET — a certified, cross-platform stack with client, server, PubSub, GDS, complex types, and source-generated tooling. Used in production across industrial control, manufacturing, energy, and IoT systems.
📦 What it is
- A full-stack OPC UA implementation — Core / Client / Server / PubSub / GDS / LDS / Complex Types / Device Integration / Positioning libraries built on .NET, with UA-TCP and HTTPS transports.
- Cross-platform — runs on .NET 10, .NET 9, .NET 8 (LTS), .NET Framework 4.8, and .NET Standard 2.1; ships Native-AOT-friendly assemblies.
- Certified for compliance — the reference server has been certified through an OPC Foundation Certification Test Lab and is continuously verified against the latest Compliance Test Tool (CTT).
- Companion-spec coverage — Part 9 (Alarms & Conditions), Part 11 (Historical Access), Part 13 (Aggregates), Part 16 (State Machines), Part 17 (Alias Names), Part 18 (Role Management), Part 20 (File Transfer), Part 100 (Device Integration), Parts 210/211 (Relative Spatial Location and Global Positioning), OPC-10030 (ISA-95 Common Model) with OPC-10031-4 Job Control V1/V2, OPC 30270 / OPC UA for Asset Administration Shell V2 and V3, OPC 10100-1 (WoT Connectivity), OPC 40001-1 (Industrial Automation), OPC 40010-1 (Robotics).
- Modern developer surface — first-class
Microsoft.Extensions.DependencyInjectionhosting (services.AddOpcUa()), fluent server + client builders, source-generated NodeManagers and DataTypes, and an MCP server so LLMs / Copilot can drive an OPC UA client.
For the full feature breakdown see OPC UA Profiles and Facets and the What's New in 2.0 tour.
🚀 Getting started
You need the .NET 10 SDK to build the repo. From the repository root:
dotnet restore UA.slnx
dotnet build UA.slnx
For the supported target frameworks and platform notes see
the Developer Guide. The official NuGet packages
are published to nuget.org under the OPCFoundation.NetStandard
prefix — the meta package
OPCFoundation.NetStandard.Opc.Ua
pulls in everything, or reference individual packages directly, e.g.
OPCFoundation.NetStandard.Opc.Ua.Client for clients or
OPCFoundation.NetStandard.Opc.Ua.Server for servers. Preview builds from
every successful master build are available from the
GitHub Packages NuGet feed.
Official public 2.0 preview releases are also on nuget.org. Enable prerelease
packages and use 2.0.0-preview.* to float to the latest published
2.0.0-preview.N release.
Samples
The stack also includes a large collection of platform-independent sample applications that turn its core services and companion models into runnable client/server workflows. More applications, including platform-specific examples, are available in the companion OPC UA .NET Samples repository.
Developer tools
- OPC UA MCP Server — installable .NET tool and container that exposes OPC UA client operations as MCP tools for LLMs and Copilot. The tools also ship as libraries (
…Opc.Ua.Mcp.Core,.PubSub,.Diagnostics,.PubSub.Diagnostics) so an application can embed them next to its own MCP tools.
🔧 Migrating from 1.5.378 to 2.0
The 2.0 release introduces breaking API changes, and comes with a full prescriptive migration guide that links to per-area documentation for the migration sub-topics.
Most of the mechanical migration work is automated:
OPCFoundation.NetStandard.Opc.Ua.MigrationAnalyzerNuGet — install it in your project to get 26 analyzer rules throughUA0030(excludingUA0013,UA0016,UA0017, and the shim-onlyUA0029) plus one-click code fixes for the patterns in the guide. Setup steps are in the package's NugetREADME.md.- Migration agent skill — the
opcua-v20-migrationskill walks Copilot / Claude / any coding agent through installing the NuGet, runningdotnet format analyzersto apply auto-fixes, and handling the small residual manual patterns. The skill knows which sub-doc to load for each symptom so it stays context-efficient.
Copilot CLI discovers the skill automatically inside a clone. To install it for use in any repository:
copilot plugin marketplace add OPCFoundation/UA-.NETStandard
copilot plugin install opcua-v20-migration@opcua-dotnet
If you are still on 1.x and not ready to upgrade, stay on the
master378
branch — it continues to receive security and critical-bug fixes.
🤝 Contributing and license
Community contributions are welcome. Fork the repository, make your changes on a branch, and open a pull request; see CONTRIBUTING.md for the contribution workflow.
Contributors must sign the OPC Foundation Contributor License Agreement (CLA). The CLA "I AGREE" gate is presented automatically on your first PR.
The project is licensed under the OPC Foundation MIT License. Report security vulnerabilities via the process documented in SECURITY.md.
📚 Further reading
- Documentation index — every per-feature doc with a one-line description.
- What's New in 2.0 — narrative tour of the 1.5.378 → 2.0 changes grouped by theme and layer.
- OPC UA Profiles and Facets — facets / transports / security policies the stack implements.
- Migration Guide — prescriptive
per-version migration reference (links to
docs/migrate/2.0.x/). - OPC UA Online Reference — the official OPC 10000 series specification index.
- Preview Nuget package feed —
prerelease builds from every successful
masterbuild.