# Description Make startup-composed application NodeManagers participate in the live lifecycle and bind imported NodeSet2 Method argument properties to their typed `MethodState` children. This change: - adopts application NodeManagers created before startup into `INodeManagerLifecycle.Registrations` after server startup succeeds, while keeping diagnostics, configuration, and core managers protected; - retains per-manager startup external-reference ownership and exact routing positions so reload, removal, rollback, overlapping namespaces, synchronous adapters, and server restart preserve existing behavior; counted immutable reference snapshots avoid quadratic startup matching; - rejects duplicate factory output across active, unpublished, and retired lifecycle generations without deleting or disposing the live manager; callers can catch the public `NodeManagerAlreadyRegisteredException`; - binds valid namespace-zero `Argument[]` `PropertyType` `InputArguments` and `OutputArguments` Variables to `MethodState.InputArguments` and `MethodState.OutputArguments` from either `HasProperty` direction, without requiring `ParentNodeId`, including local namespace-URI reference targets; - preserves authored metadata during NodeSet typed-child promotion without changing the initialization behavior of unrelated generated nodes; - retains generic-import guards for custom and malformed signatures, duplicate standard-signature validation, and upstream factory-driven generated-slot replacement and reconciliation callbacks; - updates lifecycle and Runtime NodeSet documentation and clarifies `OnServerStartedAsync` timing for both `StartAsync` overloads, including the unopened default host returned to the caller. This is a focused follow-up to #4418. That PR preserves registrations from multiple fluent builders, but does not change lifecycle ownership or NodeSet child typing. The branch includes upstream `master` through `da7412c42`, including #4396, #4432, #4437, #4438, and #4440. The completed review fixes in `686d0561f` are included. The latest base merge (`a29fc6ca8`) combines them with #4432's shared batch/fluent importer and generated state factories. One iterative linker supports available parent nodes, deferred parent side tables, application-owned handles, and placeholder reconciliation while retaining reference-driven Method argument binding and URI handling. Upstream cancellation, GDS assembly renames, certificate leak scoping, and xRegistry changes are preserved. ## Related Issues - Fixes #4421 - Fixes #4422 ## CI regression fix `e1a4436f0` fixes the GDS failure reported on Ubuntu and macOS. Copying permission metadata in general `NodeState` initialization applied `SecurityAdmin`-only defaults to generated GDS custom certificate groups and denied their existing GDS-admin Browse requests. Metadata preservation is now confined to NodeSet typed-child promotion; imported Method argument permissions remain intact, while unrelated generated nodes retain their existing initialization behavior. Local Release validation also exposed a 260-character certificate path in the startup-failure test added by this PR. Its isolated PKI now uses a short temporary path. No assertions, authorization checks, or CI gates were weakened, and no pre-existing tests were changed. ## macOS ARM64 NativeAOT suspension Per maintainer request, `a15971f32` suspends only the failing `macos-latest` / `osx-arm64` NativeAOT matrix entry. Re-enabling it once the compiler contains the runtime fix is tracked in #4443. Intel macOS, Linux, and Windows NativeAOT coverage, managed macOS tests, and all other CI gates remain enabled. This is an explicit coverage suspension, not a claim that the underlying compiler/linker defect is fixed. The macOS ARM64 NativeAOT job on `a29fc6ca8` fails during native linking with `ld: Assertion failed: (_addend == uniqueIndex && "too many large addends")`. Both attempts of [run 34191755950](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/34191755950) hit the same assertion before the native test executable can run; the build/test summary failure is downstream. This matches the NativeAOT Mach-O relocation issue in dotnet/runtime#119380, fixed by relocation-anchor emission in dotnet/runtime#124721 and its .NET 10 backport dotnet/runtime#132171. The failing `Microsoft.DotNet.ILCompiler` 10.0.11 package's nuspec points to `dotnet/dotnet` commit `e2f47b0110ed922f21a1522da67279133ce28f32` (July 23); its object writer does not contain the anchor fix merged on August 12. Version 10.0.11 is currently the latest stable package. The base commit passed on the same runner image and SDK, so this is not being dismissed as a generally broken runner or a test flake. The precise PR-specific object-layout trigger has not been isolated. A compiler containing the relocation fix is needed before restoring the lane. No test code, assertions, coverage thresholds, or shared tooling settings were changed. ## Validation Latest base-merge validation on both `net10.0` and `net48`, Release: - Import helpers and argument-binding regressions: 51 passed per framework. - Batch/fluent import, generated-state overlays, runtime/startup lifecycle, cross-source references, routing, reference snapshots, and node-authoring selection: 344 passed per framework. - Merge-specific cases cover available Method parents with forward/inverse and URI/index references while retaining an application-owned `NodeId` handle. - The unchanged upstream `NodeSetImportIntegrationTests.cs:210` CA1861 warning remains; no diagnostic suppression or unrelated cleanup was added. Release CI-fix validation on both `net10.0` and `net48`: - `CustomCertificateGroupIntegrationTest`: 4 passed, including the unchanged CI failure. - `UANodeSetHelpersTests`: 8 passed, including imported security metadata. - `StartupRuntimeNodeSetLifecycleTests`: 5 passed. Earlier Debug merge and review validation on both frameworks: - Lifecycle, RuntimeNodeSet, fluent, and OperationContext selection after merging `978e6d1af`: 638 passed per framework. - Startup/transport-binding and RuntimeNodeSet integration selection after merging `017856f4a`: 28 passed per framework. - Public exception contract and duplicate-registration selection in `fbf08428b`: 6 passed per framework. Targeted test invocations rebuilt the affected projects successfully. The full `UA.slnx` suite was not rerun locally. ## Checklist - [ ] I have signed the [CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf) and read the [CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md) doc. - [x] I have added tests that prove my fix is effective or that my feature works and increased code coverage. - [x] I have added all necessary documentation. - [x] I have verified that my changes do not introduce (new) build or analyzer warnings. - [ ] I ran **all** tests locally using the **UA.slnx** solution against at least .net **framework** and .net **10**, and all passed. - [ ] I fixed **all** failing and flaky tests in the CI pipelines and **all** CodeQL warnings. - [x] I have addressed **all** PR feedback received. --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 2bb8a834-7695-4ae6-84cb-2471c76d1b12
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.