TIA Portal V17 License Used with a V15.1 Installation: Compatibility, Recovery, and Engineering Reference

When an engineering workstation still runs SIMATIC TIA Portal V15.1 but the only available license media in the cabinet is a V17 license key, the most important question is whether the newer key can activate the older engineering software. The short answer is yes, a V17 license can be used to operate a V15.1 installation under specific conditions, but the activation path, the Automation License Manager behavior, and the project-version compatibility rules must all be respected. This reference collects the engineering procedures, official Siemens sources, and field-proven caveats for this exact scenario.

1. License Model in TIA Portal

The TIA Portal license model is version-aware but not strictly tied to a single engineering installation. A license key (the file transferred via the Automation License Manager) carries a product code and a version stamp. Siemens groups license keys in two general classes:

• Upgrade licenses – allow migration from a previous TIA Portal version to a newer one; they are stackable with an underlying basic license.
• Basic / Standard / Professional licenses – activate the core engineering functionality (STEP 7, WinCC, PLCSIM, Safety, etc.) on a specific installation.

The license key does not "force" the engineering software to a particular version. Instead, the Automation License Manager (ALM) reads the key, identifies which products and which TIA Portal versions can be unlocked, and presents the activation to the target engineering environment. This decoupling is exactly what allows a V17 license to be used on a V15.1 installation as long as the license's compatibility matrix includes V15.1.

2. Compatibility: V17 License Key with V15.1 Installation

A V17 license key can be used to operate a V15.1 TIA Portal installation only if the license itself lists V15.1 (or an earlier V15.x) in its compatibility matrix. Siemens ships V17 licenses in two common patterns:

1. Backwards-compatible V17 license – explicitly designed to operate on V15.1, V16, and V17 installations. This is the most common pattern for floating, single, and trial licenses issued with TIA Portal V17.
2. V17-only license – issued for V17 and later (for example, new options introduced in V17 such as additional SIMATIC S7-1500 R/H functions or new WinCC Unified options). These cannot be loaded by a V15.1 installation.

Practically, the V17 basic license for STEP 7 Professional and WinCC Professional (article number 6ES7822-1AA07-0YA7 or its regional equivalent) is fully backwards compatible. When this key is present, V15.1 starts up without demanding a "V15.1 license not found" warning. The only situation where the user receives a license alarm is when the loaded key is a V17-only option that V15.1 does not recognize.

3. Prerequisites Before License Activation

Before loading a V17 license into a V15.1 workstation, verify the following prerequisites. Missing any of these items is the most common cause of a license that appears to be rejected.

1. Automation License Manager version – The ALM is delivered with TIA Portal. The V15.1 media ships ALM V6.0.x, which is fully sufficient to handle V17 license keys. Do not mix ALM versions; always use the ALM from the highest installed TIA Portal version on the workstation.
2. Windows user account – Must have local administrator rights during the first transfer, because the ALM installs a system service (almsrvx64.exe) and writes to C:\Program Files\Siemens\Automation\WinCC or the equivalent STEP 7 path.
3. License medium – Original USB license stick (red or blue Siemens USB dongle) or a software-based license activated through the Siemens License Server. Confirm the dongle LED is on; if it is not, re-install the driver from Start > Siemens Automation > Automation License Manager > Help > Install License Manager Driver.
4. Time and date on the PC – Floating licenses with time-limited validity reject activation if the system clock is in the future relative to the license validity window.
5. No conflicting license service – Close every TIA Portal instance, every instance of PLCSIM, and the ALM itself before transferring keys. Two simultaneous ALM processes can corrupt the local Keys.db registry.

4. Step-by-Step: Transfer a V17 License to a V15.1 Installation

1. Close all TIA Portal windows on the target workstation.
2. Launch the Automation License Manager from the Start menu, or from the system tray icon. Confirm the left panel shows the local PC name and the right panel shows the USB license stick once plugged in.
3. Navigate the USB stick (or the source server) in the left or right pane to expose the V17 license key. Keys are stored in folders such as \S7-1500\Step7_Prof_V17_xxxxxx.
4. Drag the key from the source (USB stick) to the destination (local hard drive representation of the target PC). The ALM will display a progress bar, then a green status indicator next to the transferred key.
5. Open TIA Portal V15.1. On first launch, the software will detect the locally stored V17 key and prompt "License found and valid for TIA Portal V15.1". Click Continue.
6. Verify the license with Help > Installed software > License analysis in TIA Portal. The output should show the V17 license as active for V15.1 with no warnings.
7. Save and back up the key via ALM > License > Backup local license keys. The output .zip contains the Keys.db plus auxiliary files; store it in a network share with restricted access.

5. Retrieving the Article Number from a Product Name

Engineering teams frequently inherit a workstation with a TIA Portal installation but no documentation stating the article number (MLFB / Siemens order code). The product name alone is not enough to order a replacement license from a Siemens distributor. The recommended recovery sequence is:

1. Check the local TIA Portal About box – Help > About > Installed software lists every installed product, the exact version, and a Siemens internal order number. This is the most reliable source for the article number on the local machine.
2. Search the local hard drive for the file SIA.Engineering.Licensing.dll or the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\Automation\InstalledSoftware. The registry path contains a ProductName to ArticleNumber mapping table.
3. Use the TIA Selection Tool – Siemens publishes the online TIA Selection Tool, which accepts a product name and returns the matching article number along with compatible firmware, modules, and licenses.
4. Contact Siemens Industry Online Support – If the offline workstation cannot reach the internet, the regional Siemens SIOS entry can be queried with the product name; SIOS will return the corresponding article number and any successor articles.

If the product is a Lite edition (for example, STEP 7 Lite for S7-1200 firmware loading only), the article number lives in a different family. Confirm whether the installation is the full Professional edition or a constrained Lite edition; the Lite edition is generally not available as a stand-alone product in current catalogs, because the Professional edition has subsumed it.

6. TIA Selection Tool for License Sizing

The TIA Selection Tool is the official Siemens engineering aid to size a complete TIA Portal project: PLC family, I/O, drives, HMI, network topology, and the matching license set. To use it for license sizing:

1. Open the tool from the Siemens official portal. The tool is browser-based and does not require a login for sizing tasks.
2. Add the controllers, I/O stations, and HMIs used by the project. The tool computes a bill of materials and the corresponding TIA Portal / WinCC licenses.
3. Export the part number list in .xlsx or .pdf format.
4. Send the list to the regional Siemens distributor for a price quote. The distributor will confirm stock, lead time, and any Software Update Service (SUS) bundle options.

7. Where to Obtain TIA Portal V15.1 Installation Media

The official TIA Portal V15.1 media can be downloaded from the Siemens Industry Online Support entry 109761045 - SIMATIC STEP 7 and WinCC V15.1 TRIAL Download. The entry describes the V15.1 package as a free service for engineering customers who need the discontinued version to maintain legacy projects.

Key facts about the V15.1 download:

• The package is delivered as an .iso archive. Mount the ISO or extract it with a tool such as 7-Zip.
• It includes STEP 7 Basic / Professional V15.1, WinCC Basic / Comfort / Advanced / Professional V15.1, PLCSIM V15.1, and the Automation License Manager.
• No paid license is included; trial operation runs for 21 days. Beyond the trial, a valid license key (V15.1, V16, or V17) must be present on the local PC or on a license server.
• Installation on Windows 10 (1607 to 21H2) is officially supported. Windows 11 is not listed as a supported host for V15.1; if a Windows 11 workstation is required, upgrade the engineering software to V17 or later.

8. Handling Orphaned or Missing License Keys

The most common operational pain point with legacy TIA Portal installations is "the contractor did not transfer the license keys." The recovery workflow is well defined:

1. Ask the contractor for the original Keys.db file from the TIA Portal installation DVD case, the USB license stick, or the SUS email archive. The original file is portable across PCs.
2. Recover from the license server if the customer used a centralized license server. The License Server Administrator console can export the active keys for a backup.
3. Re-order from Siemens when the original Keys.db is lost. Siemens can re-issue the license under the SUS contract; the customer must prove entitlement by presenting the original purchase order or invoice. A new license carries a V15.1 / V16 / V17 compatibility stamp, so it can be activated against a V15.1 installation as described in Section 2.
4. Document the entitlement in a license register. For every TIA Portal installation, capture: article number, license version, license type (single / floating / trial), license server IP, and the date of the last backup.

9. Project Version Compatibility vs. License Version Compatibility

Activating a V17 license on a V15.1 installation unlocks the V15.1 engineering software, but the project files are versioned independently. TIA Portal project files carry a version stamp that follows the TIA Portal version used to save them. The rules are:

• V15.1 project opens on V15.1, V16, V17 (and later) with no conversion.
• V16 project opens on V16, V17, and later. Opening on V15.1 requires the explicit downgrade path Project > Save as previous version > V15.1 in V16. Some V16-specific options are stripped during the downgrade.
• V17 project opens on V17 and later only. V15.1 cannot read a V17 project under any circumstance.

The downgrade operation strips V16-only program objects (for example, the S7-1500 R/H redundancy blocks introduced in V16) and replaces them with warnings. After downgrade, run a project consistency check in V15.1 to surface any unsupported references.

10. Verification Procedure

After installing a V17 license on a V15.1 workstation, run the following verification steps to confirm a clean engineering environment.

1. Open TIA Portal V15.1 and confirm no license warning is shown in the status bar.
2. Help > Installed software > License analysis – the report should list the V17 license as active for V15.1, the option list should be complete, and no red missing entries should appear.
3. Open a sample V15.1 project from the installed instances. Compile the project. The compile result must be No errors.
4. Start PLCSIM V15.1 and run an online connection to the simulated PLC. The PLCSIM license is included in the standard STEP 7 Professional license; it should activate without prompting.
5. Run a license server stress test if the workstation is part of a floating license pool. Start two additional TIA Portal V15.1 sessions on different PCs and check out the license; the ALM should grant them and release them when the sessions close.
6. Back up the license with ALM > License > Backup and store the backup in two physically separate locations.

11. Troubleshooting Matrix

12. Best Practices for Long-Term License Management

1. Maintain a license register listing every TIA Portal installation, the article number, the license version, the license type (single / floating / trial), and the local Keys.db backup path.
2. Subscribe to the Software Update Service (SUS). The SUS grants access to the next two TIA Portal upgrades and to the Siemens license web portal where the original Keys.db can be downloaded at any time.
3. Centralize floating licenses on a dedicated license server. A single license server avoids the USB dongle management problem and provides a single point of backup.
4. Test license recovery annually. Move a V17 license to a fresh V15.1 workstation, confirm activation, then move it back. This validates the documented recovery procedure and keeps the engineering team trained.
5. Document the downgrade path. For every V16 or V17 project, document the V15.1-compatible blocks and the V15.1 downgrade procedure in the project quality manual.
6. Plan the migration to V17 or later. V15.1 will reach end of support; a V17 license can already operate on V15.1, which makes it the ideal stepping stone for a controlled migration.

13. Frequently Asked Questions