Siemens TIA Portal V21: 7 New Features That Actually Change Your Daily Work

Siemens released TIA Portal V21 in December 2025, and by April 2026 it is the version most engineers are either rolling out or evaluating. Unlike incremental V18→V19→V20 updates, V21 is the release where Siemens finally puts software-defined automation, proper Git integration, and a production-ready AI copilot into the same package.

This is a hands-on review of what actually matters in daily engineering - not the marketing bullet list. If you are still on V19 or V20, this guide tells you whether the migration is worth doing now or waiting for the first service pack.

1. Native Git Integration - Finally a Real VCS for PLC Code

The single biggest change in V21 is a new export format that enables seamless integration with Git and other version control systems for LAD, FBD, SCL, data blocks, PLC data types, and mixed-language blocks.

Before V21, PLC projects were one giant binary blob. Diffs were impossible. Code review meant "let's open two instances of TIA Portal side by side." Pull requests, branching, CI pipelines - out of reach for 99% of teams.

V21 changes the model completely:

// example.scl - now diffable line-by-line in Git
FUNCTION_BLOCK "FB_PumpControl"
VAR_INPUT
    Start_Cmd : BOOL;
    Setpoint  : REAL;
END_VAR
VAR_OUTPUT
    Running   : BOOL;
END_VAR
    IF #Start_Cmd AND NOT #Fault THEN
        #Running := TRUE;
    END_IF;
END_FUNCTION_BLOCK

You can now branch, merge, review, and automate. CI pipelines running pytest-style unit tests on FB_* blocks are finally practical. For distributed teams - mandatory.

My take: this alone justifies the V21 jump. If your team does code review or works across multiple sites, you will feel the difference in week one.

2. Engineering Copilot TIA Standard - AI That Actually Helps

Siemens shipped Engineering Copilot TIA Standard, a generative AI assistant embedded in the IDE. Natural language in, PLC code and HMI visualizations out.

What it does well in V21:

• Generates SCL function blocks from a description ("FB for two-stage compressor with interlock")
• Writes WinCC Unified screen layouts from a prompt
• Explains unfamiliar library blocks in plain English
• Suggests variable names consistent with your project's style

What it still cannot do: debug live runtime issues, replace a proper test rig, or guess what the client actually meant in a vague spec. Treat it as a fast autocomplete for the boring 70% of code.

Reality check: the Copilot is cloud-based and requires a Siemens ID and an active license. Offline-only customers (pharma, defense) cannot use it yet - the on-prem variant is announced but not released.

3. S7-1200 G2 Gets Full OPC UA

The SIMATIC S7-1200 G2 now has full OPC UA server and client functionality - not just the basic data access profile. In V21 you get methods, events, alarms, and pub/sub on hardware that costs a fraction of an S7-1500.

This matters because the G2 is now a legitimate edge controller. You can build an ISA-95 Level 2 data bridge without an S7-1500 or an extra IPC, and connecting a compact controller to MES, SCADA or cloud gateways no longer needs an extra protocol converter.

Python side - unchanged, still asyncua:

# edge_subscribe.py - read tags from an S7-1200 G2 over OPC UA
import asyncio
from asyncua import Client

async def main():
    async with Client("opc.tcp://plc-g2.local:4840") as client:
        node = client.get_node("ns=3;s=PumpStation.Flow")
        while True:
            print(await node.read_value())
            await asyncio.sleep(1.0)

asyncio.run(main())

4. WinCC Unified: Redundant Server Architectures

SCADA built on WinCC Unified can now run in redundant server architectures - hot-standby, automatic failover, no data loss during switchover. Previously this required Classic WinCC or third-party redundancy layers.

For any plant with a real uptime SLA, this is the feature that makes Unified viable for greenfield projects. Pharma, food and beverage, automotive press shops - the conversation shifts from "Classic or Unified" to "which Unified topology."

5. New WinCC Unified Screen Editor

The Screen Editor was rebuilt from the ground up. Most layout operations that previously required round-trips to the Properties panel or modal dialogs are now direct-manipulation. Grid snapping, alignment guides, multi-select edit, and live property changes work like a modern design tool.

If you've been doing WinCC Unified HMI screens and cursing the click count, V21 cuts it roughly in half. First time I can recommend WinCC Unified HMI work without a long caveat about the editor.

6. Multicore Motion Control - Up to 30% Faster

On newer multicore PLCs (1516T-3, 1517T-3, 1518T-4), Motion Control Technology Objects can now be distributed across two cores. Enable Improve System Performance inside the Technology Object OB and processing moves off the single core it used to live on.

Siemens claims up to 30% reduction in Technology Object processing time. Real-world - on a multi-axis cam-table pick-and-place rig, I measured ~22% cycle time improvement on an S7-1517T. Not always 30%, but always positive.

This is the first release where you can credibly run 16+ coordinated axes on a single CPU without reaching for a SIMOTION.

7. Safety Integrated - Test Mode and Faster Commissioning

Safety Integrated in V21 gets a Safety Test Mode that lets you force F-I/O states during commissioning without downloading test logic, and F-block compare that shows you exactly what changed between two F-block versions with the checksum implications spelled out.

For ISO 13849 PL d / IEC 62061 SIL 2 projects this is a massive time saver. Previously, proving that a small change didn't affect the safety integrity required a full re-check of checksums and a manual diff. V21 gives you both in the UI.

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TIA V20 vs V21 - Quick Comparison

Should You Upgrade?

Upgrade now if any of these apply:

• Team of 3+ engineers, distributed, needs real code review → Git integration alone pays for the migration
• Greenfield WinCC Unified SCADA with uptime requirement → redundancy is the deciding feature
• Motion-heavy application on multicore hardware → the 20-30% cycle improvement is free
• Safety projects where change management eats hours per revision

Wait for SP1 if:

• You are on a validated pharma/medical project where requalification is expensive
• You need offline-only Copilot (not yet available)
• Your OEMs haven't released V21-compatible libraries yet

Migration Checklist (V20 → V21)

1. Back up your V20 project and tag it in your current VCS (or at minimum, zip + archive).
2. Install V21 side-by-side with V20 - both can coexist.
3. Migrate a non-critical project first to calibrate timing and catch library incompatibilities.
4. Re-check checksums on all F-blocks after migration before any SAT/FAT.
5. Regenerate hardware configuration for any S7-1200 G2 stations to pick up full OPC UA.
6. Export your project to the new Git-friendly format and commit the baseline - this is the snapshot you'll diff every future change against.

TIA Portal V21 as an engineering framework - what is in the package?

TIA Portal (Totally Integrated Automation Portal) is the Siemens engineering framework for PLC programming, HMI and drive configuration. Version 21 of its engineering framework bundles several products that share one project and one user interface:

• SIMATIC STEP 7 V21 (Basic or Professional) - PLC programming in LAD, FBD, SCL, STL and GRAPH.
• STEP 7 Safety V21 (Basic or Advanced) - fail-safe programs for F-CPUs, with the new Safety Test Mode described above.
• SIMATIC WinCC Unified and WinCC Basic, Comfort, Advanced and Professional - HMI panels and PC-based visualization, including WinCC Unified PC runtimes.
• SINAMICS Startdrive - configuration and commissioning of SINAMICS drives.
• PLCSIM and PLCSIM Advanced - testing and simulation functions without real hardware.

All products in TIA Portal V21 must have the same version, so plan the installation of STEP 7, WinCC and Startdrive together.

With this release Siemens continues the transition to software-defined automation: Git-friendly text export, AI support for engineering and more open interfaces aim at higher engineering efficiency for machine builders who face a shortage of skilled workers. Cyber security also gets more attention, because modern controllers are connected to plant networks and the cloud, for example through TIA Portal Cloud, the browser-based way to use the engineering system without a local installation.

Installation of STEP 7 Professional V21 and parallel installation to other STEP 7 versions

Before you install, check the system requirements and the compatibility list on Siemens Industry Online Support. A few practical rules help avoid surprises:

• Parallel installation with other TIA Portal versions - TIA Portal V21 can be installed next to V20 and older TIA Portal versions on the same PC, so you can keep maintaining existing machines while you test the new version.
• Parallel installation to other STEP 7 and WinCC versions - STEP 7 V5.x (SIMATIC Manager), WinCC V7 and older WinCC Professional versions have their own compatibility rules, and the parallel installation of WinCC Professional runtimes needs special attention. Siemens publishes them in "Parallel Installation of TIA Portal V21 (STEP 7, WinCC)" (entry 109995165). Read it before you install V21 on a PC that already runs WinCC RT Professional or STEP 7 V5.x.
• Licenses - licenses are managed with the Automation License Manager. Without a license you can start the trial version.
• Updates - after the main installation, install the latest update for V21 and the hardware support packages (HSP) you need.
• Product information - read the readme and product information for STEP 7 Safety V21 and WinCC V21 before you migrate fail-safe programs or HMI devices, because they list known limitations of the current release.

Opening projects from earlier versions and migration of projects from STEP 7 V5.x

Opening projects from earlier versions works in one direction only: the project is upgraded and can no longer be opened in the old version. For projects from STEP 7 V5.x and WinCC flexible, Siemens provides a migration path into TIA Portal, but not every legacy function is supported, so expect manual work after migration. Projects from older TIA Portal versions are upgraded when you open them, while very old versions may need an intermediate step. For the move from V20 to V21, use the checklist above and test with simulation in PLCSIM before you download to a real CPU. If you are new to the S7-1200 hardware, start with our Siemens S7-1200 PLC tutorial. For a practical introduction to the Git workflow described in feature 1, read TIA Portal version control with Git, and to learn STEP 7 programming from the basics, see our Siemens TIA Portal LAD/FBD course.

TIA Portal V21 - FAQ

Q: Is TIA Portal V21 backward compatible with V20 projects? A: Yes, V21 opens V20 projects and migrates them. The migration is one-way - once saved in V21, you cannot open the project in V20 again, so keep a V20 archive.

Q: Does Engineering Copilot work offline? A: No - the Standard Copilot in V21 requires a cloud connection and a Siemens ID. An on-prem variant has been announced but is not yet available.

Q: Which PLCs support multicore motion distribution? A: Multicore S7-1500T CPUs, specifically 1516T-3 PN/DP, 1517T-3 PN/DP, and 1518T-4 PN/DP. The feature is enabled per Technology Object OB.

Q: Do I need a new license for V21? A: If you have an active Software Update Service (SUS), V21 is included. One-time V20 licenses require an upgrade or a new purchase.

Q: When will TIA Portal V21 SP1 be released? A: Check the "TIA Portal V21 Updates" page on Siemens Industry Online Support (entry 109989775). It lists the latest update and service pack for STEP 7, WinCC and the other products in TIA Portal V21.

Q: Is TIA Portal V21 free to download? A: The software is downloaded from Siemens Industry Online Support with a Siemens ID, but it needs a license. Siemens offers a trial version, so you can test it for 21 days before you buy. The trial software is a good way to check whether your projects and libraries migrate cleanly.

Q: What is the difference between STEP 7 Basic and STEP 7 Professional V21? A: STEP 7 Basic is for the S7-1200 family (including the S7-1200 G2). SIMATIC STEP 7 Professional V21 also covers the S7-1500, S7-300/400 and ET 200SP CPUs and is the version most machine builders use.

Q: How do I uninstall TIA Portal V21? A: Close all TIA Portal applications and remove the V21 products from Windows Settings > Apps (or run the TIA Portal setup and choose to remove products). Remove all V21 products together, and leave other installed versions such as V20 untouched.

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