WinCC Unified V21: redundancy, a Data Hub, and TIA projects you can finally Git
TIA Portal V21 was announced at SPS in November 2025 and started shipping in early December. Most version bumps are incremental. This one closes the two gaps that have kept Unified out of serious SCADA tenders — and adds something PLC programmers have wanted for twenty years.
Redundant servers, at last
V21 brings hot-standby redundant WinCC Unified server pairs with automatic failover. Until now, a SCADA job that needed high availability meant falling back to WinCC V7 or a third-party package — Unified simply couldn’t quote it. That excuse is gone. The catch: it’s V21-only, so redundancy requirements now set the minimum Portal version for the whole project.
The Data Hub
The new WinCC Unified Data Hub is a central archive that collects process values, alarms and audit trails from multiple Unified PC runtimes into one place. If you run several lines each with their own runtime, this is the plant-wide history layer that previously needed a separate historian or a hand-rolled SQL pipeline.
Git for TIA projects
V21 adds a text-based export of program blocks — LAD and FBD included, not just SCL — plus DBs and PLC data types. Diffable text means real version control: branching, line-by-line code review, CI checks on standard tooling. We already run AI-assisted SCL workflows that lean on text round-tripping; this makes the same discipline possible on graphical code.
Two cautions. The V20 to V21 project upgrade is one-way — there is no save-back, so don’t migrate a live customer project mid-commissioning. And the Engineering Copilot that now embeds in the IDE is cloud-hosted: it needs a Siemens ID and an internet connection, which rules it out on air-gapped sites.
The panel range in 2026
The Unified hardware lineup now covers Basic Panels (4–12”, integrated web client, no recurring licence costs), Comfort Panels (7–22”), the machine-mounted PRO and Hygienic variants, and HTML5 Industrial Web Panels. Unified Basic Panels have been stocked in Australia through APS Industrial since mid-2024, which makes Unified the default choice even at the low end of a project. The one remaining hole — a Unified Mobile Panel — is announced for the first half of 2027.
Worth bookmarking
- The official tia-portal-applications GitHub org: the Custom Web Control development guide (refreshed October 2025), a Web Toolbox CWC, and an add-in that exports every screen JavaScript in a project to readable files — invaluable for review and diffing.
- SIOS 109758536 — the canonical Unified JavaScript scripting tips document.
- SIOS 109768002 — the Comfort-to-Unified migration guide, if a panel refresh is on your maintenance plan.
- Community tooling around Unified’s GraphQL API is maturing fast, including MCP servers that let AI assistants read live runtime data — the same pattern our on-prem maintenance assistant uses.