Overview
Siemens TIA Portal uses a centralized license management model where one license key can authorize multiple software versions across the engineering and runtime families. When you purchase a WinCC license for TIA Portal V20, that license key is version-independent for the current and all prior TIA Portal releases, including V15.1. This is a significant operational advantage when you maintain long-lived projects on older TIA Portal versions but want to standardize license procurement on the latest available release.
Engineers commonly ask: "Can I buy a V20 license and use it on a V15.1 project?" The short answer is yes. The full answer involves understanding how Siemens structures engineering licenses, runtime licenses, and option packages, plus the exact behavior of the Automation License Manager when it encounters a mixed-version environment.
TIA Portal License Architecture
Siemens separates licenses into two primary categories that operate independently on the same license server or USB dongle.
| Category | Purpose | Examples |
|---|---|---|
| Engineering Licenses | Authorize configuration and programming tools inside TIA Portal | STEP 7 Professional, WinCC Comfort/Advanced/Professional, Safety Advanced, PLCSIM |
| Runtime Licenses | Authorize HMI/SCADA runtime software that executes on the target PC or panel | WinCC Professional Runtime (16, 64, 128, 256, 512, 1024, 2048, 4096, 8192 PowerTags), WinCC Unified PC Runtime, WinCC Unified Comfort/Comfort RT |
| Option Licenses | Add-on functions within engineering or runtime | WinCC Recipes, WinCC Logging, WinCC Audit, Sm@rtServer, OPC UA Server |
Each license key is stored in the Automation License Manager (ALM) and bound to either a physical USB license key (hardlock) or a software-based license container on a designated license server. The ALM is the only authoritative source for license validation when TIA Portal or WinCC Runtime starts.
Downward Compatibility: How It Works
Siemens license keys are issued with a version-independent identifier that maps to a product family rather than a single version. When you activate a TIA Portal V20 license, the ALM stores a record that any TIA Portal version from V15.1 up to V20 (and beyond, if the license is forward-compatible) can validate against it.
Field-verified behavior across the TIA Portal V13/V14/V15.1/V16/V17/V18/V19/V20 release lines confirms that a license purchased for the latest installed TIA Portal version will validate against any older TIA Portal installation on the same machine or against the same license server. This applies to engineering licenses, runtime licenses, and option packages alike.
License Types and Their Versions
| WinCC License | Engineering Function | Runtime Required |
|---|---|---|
| STEP 7 Basic/Professional | PLC programming; configuration of Basic Panels and SIMATIC S7-1200/1500 CPUs | No WinCC license needed for Basic Panels only |
| WinCC Comfort | Configuration of Comfort Panels, Unified Comfort Panels, and Mobile Panels | Runtime is included in the panel firmware (no separate runtime key) |
| WinCC Advanced | Configuration of all Comfort Panels plus WinCC Runtime Advanced on PC-based systems | WinCC Runtime Advanced license (16, 128, 512, 2048, 4096 PowerTags) |
| WinCC Professional | Configuration of all panels and PC-based SCADA including WinCC Runtime Professional | WinCC Runtime Professional (16 to 163840 PowerTags in steps) |
| WinCC Unified | Configuration of Unified Comfort Panels and Unified PC Systems | WinCC Unified PC Runtime (150, 500, 2500, 5000, 10000, 50000 tags) |
If you only need to configure a project, you need an engineering license. If you need to run the project on a target HMI or PC, you need a runtime license. The same ALM container can hold both; the same V20 key family can include both.
Supported License Combinations for V15.1 to V20
The following table documents the license behavior for projects originally authored in TIA Portal V15.1 when a V20 license is installed.
| Scenario | V20 License Installed | V15.1 Project Behavior |
|---|---|---|
| Open V15.1 project in TIA Portal V15.1 with V20 key on ALM | Yes | Project opens without license warnings; full editing enabled |
| Open V15.1 project in TIA Portal V20 with V20 key on ALM | Yes | Project opens; V20 prompts for upgrade; option to skip upgrade retains V15.1 target |
| Compile/runtime simulate V15.1 project in V20 with V20 key | Yes | Full compilation and PLCSIM/HMI RT simulation work; project retains V15.1 firmware targets |
| V15.1 project deployed to Runtime with V20 Runtime key | Yes | Runtime starts; PowerTag count and option packages match the V20 license tier |
| No V20 key installed, only V15.1 key on ALM | No | Works only with TIA Portal V15.1; V20 installation will not validate |
Prerequisites
- Automation License Manager (ALM) installed. The current ALM version is bundled with every TIA Portal installation. Verify in Windows Programs and Features that "SIEMENS Automation License Manager" is present, or download the latest standalone installer from the Siemens Industry Online Support portal.
- TIA Portal V15.1 SP1 or later. The V15.1 baseline must be at minimum Update 1 to be compatible with current ALM releases.
- License Certificate (CoL). The CoL is a PDF supplied by Siemens or your distributor containing the License Key (a 20-character alphanumeric string) and the order number.
- Internet access on the license server (only required for the initial activation; offline activation via License Key File (.LKF) is also supported).
- Administrative rights on the PC where the ALM service is running.
Step-by-Step: Activating a V20 License and Using It on a V15.1 Project
Step 1 – Locate the License Key
Open the Certificate of License (CoL) PDF received with your order. Note the License Key (a 20-character string, e.g., 1A2B3C-4D5E6F-7G8H9I) and the matching Product Name (e.g., WinCC Professional V20).
Step 2 – Install the License via Online Transfer
- Open Automation License Manager from the Windows Start menu.
- Connect the USB license dongle if your order is a hardlock variant.
- From the menu, select Edit → Install License.
- Enter the 20-character License Key and confirm.
- ALM contacts the Siemens License Server over HTTPS, downloads the license file, and writes it to the local ALM repository or to the connected USB dongle.
Step 3 – Verify the License Is Detected
In ALM, navigate to the local computer or USB dongle node. The newly installed WinCC V20 license should appear in the right pane with status Valid. If you see a yellow warning triangle, right-click the entry and choose Repair.
Step 4 – Open the V15.1 Project in V15.1
- Start TIA Portal V15.1.
- Open the existing
.ap15_1project. - TIA Portal will detect the V20 WinCC license in ALM and report it as the satisfying license. No additional configuration is required.
Step 5 – (Optional) Open the V15.1 Project in V20
- Start TIA Portal V20.
- Open the V15.1 project. TIA Portal prompts: "Do you want to upgrade the project?"
- Click No if you want to keep the V15.1 target firmware.
- The project opens in read-write mode using the V20 license in ALM. Compilation and download to a V15.1-target CPU or panel work without changes.
Offline Activation Procedure
If the license server has no internet access, perform an offline activation:
- On an internet-connected PC, open Siemens License Web and sign in with your Siemens account.
- Enter the License Key, generate a License Key File (.LKF), and download it.
- Transfer the .LKF to the target PC.
- In ALM on the target PC, select Edit → Install License, choose the .LKF file, and confirm.
License Key Management Best Practices
- Centralize on a license server. Install ALM as a service on a dedicated PC and have all engineering workstations connect to it. This avoids dongle swaps and lost keys.
- Document the License Key per project. Record the 20-character key, product family, order number, and expiration (if subscription) in a project register.
- Verify before migration. Before upgrading a V15.1 project to V20 targets, run the TIA Portal V20 license analysis to confirm the available V20 key covers the WinCC option packages (Recipes, Logging, Audit, Sm@rtServer) used by the project.
- Keep the CoL PDF in a safe location. Lost License Keys require a Siemens support ticket with proof of purchase to recover.
- Do not mix subscription and perpetual keys in the same ALM container without testing — the ALM will choose one, and the other may appear as "not used".
Troubleshooting Common Issues
| Symptom | Likely Cause | Resolution |
|---|---|---|
| "License not found" when opening V15.1 project in V20 | ALM service is stopped or the license server is unreachable | Start the "S7License Server" service (services.msc) and verify the license server path in V20 under Options → License Management |
| V20 license is visible in ALM but TIA Portal V15.1 reports missing | ALM version on V15.1 is too old to recognize the V20 key signature | Update ALM to the latest version on the V15.1 workstation; the V20 key will then validate |
| Runtime starts in demo mode despite V20 runtime license | PowerTag count exceeds the licensed tier | Open Runtime's License Analysis and compare active tags to the licensed count; upgrade to the next tier or reduce tags |
| "License is already in use" error when opening a second TIA Portal instance | Single-seat license is checked out by the first instance | Close the other instance, or migrate to a network license with sufficient concurrent seats |
| Project upgrade from V15.1 to V20 fails with license error | Missing WinCC option package (e.g., Recipes, Audit) on the V20 license | Purchase the missing option license for V20; V20 requires V20-tier options, not V15.1 options |
Forward Compatibility Note
Siemens documentation for TIA Portal V20 confirms that WinCC options with version-independent license keys can be used for future TIA Portal versions. In practical terms, the V20 license you purchase today will continue to validate when you later upgrade your TIA Portal installation to V21, V22, or any subsequent release that retains the same product family. This protects your license investment across the full lifecycle of your automation project.
Refer to the official Siemens TIA Portal V20 licensing documentation for the authoritative compatibility matrix: Licensing STEP 7 and WinCC - TIA Portal V20.
Procurement Recommendations
When purchasing WinCC licenses for a mixed-version environment (V15.1 active projects, V20 standard procurement), follow this decision path:
- Confirm the WinCC edition needed (Comfort, Advanced, Professional, or Unified) by reviewing the HMI panels and PC-based systems in the project.
- Order the engineering license at the latest TIA Portal version (V20 or current) to maximize forward and backward compatibility.
- Order the runtime license at the PowerTag tier that matches or exceeds the current project count, leaving 20–30% headroom for expansion.
- Add option licenses (Recipes, Logging, Audit, Sm@rtServer, OPC UA) only for the options actually configured in the V15.1 project.
- Subscribe to Software Update Service (SUS) if you anticipate migrating the project to a newer TIA Portal version within 1–2 years; SUS provides the next-version license at no additional engineering cost.
Verification Checklist
After activating the V20 license, perform the following checks before commissioning:
- Open the V15.1 project in TIA Portal V15.1 and confirm no license warnings appear in the status bar.
- Open the same project in TIA Portal V20 (decline the upgrade prompt) and confirm it opens and compiles cleanly.
- Start the HMI Runtime on the target panel or PC and verify it does not enter demo mode.
- In ALM, confirm the V20 license is the active one (right-click → Show License Usage).
- Document the License Key, order number, and TIA Portal versions in the project handover file.
Frequently Asked Questions
Can I use a TIA Portal V20 WinCC license on a V15.1 project?
Yes. TIA Portal licenses are downward compatible. A WinCC V20 license stored in the Automation License Manager will validate against any TIA Portal installation from V15.1 up to V20 and beyond, so the same key works on your V15.1 project without modification.
Do I need a separate TIA Portal license to start the software?
No. TIA Portal itself starts without a license. Only the individual engineering packages (STEP 7, WinCC, Safety) and runtime packages (WinCC Professional Runtime, WinCC Unified PC RT) require their own license keys. Purchase each component separately based on what you configure and deploy.
Does the STEP 7 license cover HMI panel configuration?
Partially. STEP 7 includes configuration rights for SIMATIC Basic Panels. Comfort Panels, Mobile Panels, and Unified Comfort Panels require a WinCC Comfort license; PC-based runtime requires WinCC Advanced or Professional; Unified PC Runtime requires the Unified PC RT license.
Can I buy WinCC Engineering and Runtime licenses separately?
Yes. Engineering and runtime licenses are independent. Buy only the engineering license if you only configure, only the runtime license if you only deploy pre-configured projects, or both if you do the full workflow in-house.
Will a V20 license work with future TIA Portal versions like V21?
Siemens documentation confirms that WinCC options with version-independent license keys can be used for future TIA Portal versions. A V20 license purchased today will continue to validate when you upgrade your TIA Portal installation to V21 or any later release in the same product family.