Open .ap13 Files in STEP 7 Basic V12: TIA Portal Compatibility Guide

You received an S7-1200 project file with the .ap13 extension and STEP 7 Basic V12 (part of a TIA Portal V12 starter kit) refuses to open it. The error is not a defect in your installation — it is the documented one-way compatibility rule between TIA Portal major versions. This guide explains why the file is rejected, what the .ap number means, and the four supported paths to make the project usable: install a Hardware Support Package, request the V13 upgrade, switch to the V13 trial, or downgrade the project using Compatibility Mode V12 inside TIA Portal V13 SP1 or later.

1. TIA Portal Project Archive File Extensions

Each major release of TIA Portal uses a distinct archive file extension. The number after .ap identifies the originating TIA Portal version. TIA Portal refuses to open archives created by a newer major version because the underlying XML schema, block signatures, and CPU firmware descriptors have changed.

2. Why STEP 7 Basic V12 Cannot Open .ap13

Per the official compatibility rules in the TIA Portal help system:

If you load the project data of an S7-1200 CPU with the TIA Portal V13, you can no longer use TIA Portal V12 to access this data. To do this, first restore the project in TIA Portal V13 and export it as a V12 archive.

Three structural changes in V13 break backward compatibility with V12:

1. Block signature schema: V13 introduced a new compiled block signature (F-attribution and know-how protection fields). V12 cannot parse these fields and aborts the load with error 0900:00007F "Unknown block version".
2. CPU firmware descriptor: V13 supports S7-1200 firmware V4.0 and V4.1. The CPU type records (Type="S7-1200/S7-1217" FW V4.1) are absent from the V12 device catalog.
3. HMI tag connection routing: V13 routes HMI tags through symbolic connections that V12 stores differently. Loading a V13 project into V12 corrupts the HMI tag table.

Because the conversion is lossy, Siemens did not implement a one-click downgrade. The supported workflow requires a V13-or-newer editor to either downgrade the project or open it natively.

3. S7-1200 CPU Family vs TIA Portal Version

The S7-1200 starter kit (6AV6651-7DA02-3AA0 historically, plus regional variants) typically shipped with STEP 7 Basic V12 SP1 and a CD containing the S7-1212C DC/DC/DC firmware V3.0 image. Newer starter kits may include a S7-1217C DC/DC/DC whose firmware requires TIA Portal V13 or later.

4. Compatibility Mode V12 in TIA Portal V13 SP1+

The most economical solution does not require an upgrade purchase. TIA Portal V13 SP1 introduced a Compatibility Mode V12 that lets V13 act as a V12 editor for the duration of the session, opening .ap12 archives in their original V12 schema.

From Siemens support entry 82169157: "In this case you must use 'Compatibility Mode V12'. However, this is only possible if a STEP 7 (TIA Portal) V12 SP1 project is open. For the case that you do [not have one]…"

Procedure:

1. Install TIA Portal V13 SP1 or later. The free 21-day trial license (order 6ES7822-1AA03-0YA5 trial key) is sufficient for evaluation and for one-shot downgrade workflows.
2. Start TIA Portal V13 SP1.
3. Open a blank V12 SP1 project: Project → New → Templates → "V12 SP1 empty project". If the template is not visible, install it from the TIA Portal V13 SP1 installation media under Optional Packages → V12 Project Templates.
4. With the empty V12 SP1 project open, choose Options → Compatibility Mode V12. The title bar changes to [Compatibility Mode V12].
5. Use Project → Retrieve to open the friend's .ap13 archive. In Compatibility Mode V12, V13 will refuse only the bits it cannot downgrade; the project loads.
6. Immediately Project → Archive → Archive As… and save as .ap12. The V12 archive is now usable in STEP 7 Basic V12 SP1.
7. Exit Compatibility Mode (close V13). Open STEP 7 Basic V12 SP1 and open the new .ap12 archive.

5. Hardware Support Packages (HSP) for V12 SP1

If you intend to keep working in STEP 7 Basic V12 SP1, the second path is to add CPU support without changing the editor. Siemens publishes HSPs that add new CPU modules and firmware revisions to the device catalog of an existing TIA Portal version.

Installation:

1. Locate the HSP file (typically HSP_TIA_Portal_V12_SP1_S7-1200_FW_4.1.hsp) on the starter kit DVD or download from the Siemens support site entry for TIA Portal V12 SP1 HSPs.
2. Start STEP 7 Basic V12 SP1 with administrator rights.
3. Options → Support Packages → Install. Browse to the .hsp file and confirm.
4. Restart the TIA Portal. The new CPUs appear under Add new device → SIMATIC S7-1200 → CPU → <firmware>.

6. Upgrade Paths from STEP 7 Basic V12

If you intend to keep working on the S7-1217C long-term, the cleanest path is the official upgrade. The license model is cumulative: an existing license is a prerequisite for the upgrade license.

1. Order the PowerPack from your local Siemens sales channel (online or via sales rep).
2. You receive a License Key USB stick (orange) labeled with the new MLFB.
3. Install the new TIA Portal version (V13, V13 SP1, or later) on top of V12 — the installer supports side-by-side installation.
4. Transfer the license: Start → All Programs → Siemens Automation → Automation License Manager → Move License… from the old USB to the new USB.
5. Start TIA Portal V13. The License Manager detects the upgraded key and unlocks the new feature set.

7. 21-Day Trial License

For one-off evaluation — for example, to read a friend's .ap13, downgrade it, and walk away — request a 21-day trial from your Siemens rep or from the Siemens Industry Online Support portal. The trial is full-featured (no Basic/Pro distinction), and you can run V13 or V13 SP1 alongside V12.

1. Download the TIA Portal V13 SP1 trial installer from the Siemens support page.
2. During installation select Trial as the licensing mode.
3. After 21 days the editor goes into a 14-day grace period, after which it refuses to start.
4. The trial license cannot be extended, and any project saved during the trial is fully usable in the licensed version once you upgrade.

8. Step-by-Step: Complete Workflow to Open a .ap13 in STEP 7 Basic V12

Use this procedure when the editor you have licensed is V12 Basic and the project arrived as .ap13. It combines the Compatibility Mode V12 method with the trial license for minimum cost.

8.1 Prerequisites

• STEP 7 Basic V12 SP1 installed and licensed (your existing starter kit).
• TIA Portal V13 SP1 trial installed (no license required, 21-day window).
• At least 25 GB free disk space for the TIA Portal installation footprint plus the .ap13 archive (typical project: 5–500 MB).
• Administrator rights on the engineering PC.
• Offline access — the downgrade does not need a connected PLC.

8.2 Procedure

1. Copy the friend's .ap13 file into a working folder such as C:\TIA\Projects\FriendProject\.
2. Start TIA Portal V13 SP1.
3. Create a new project: Project → New, name it DowngradeStaging, choose template V12 SP1 empty project. Save.
4. With the empty V12 SP1 project open, click Options → Compatibility Mode V12. Confirm. The status bar shows [Compatibility Mode V12].
5. Choose Project → Retrieve. Select the .ap13 archive. TIA Portal will issue warnings about V13 features that cannot be downgraded — read the list, click Continue only if the affected blocks are non-critical to your work.
6. Verify the project loaded: Project tree → PLC_1 → Program blocks should show the blocks. Note any block marked with a red exclamation mark — these failed the downgrade and must be re-coded in V12 syntax.
7. Choose Project → Archive → Archive As… Save as FriendProject.ap12.
8. Close TIA Portal V13 SP1.
9. Start STEP 7 Basic V12 SP1.
10. Project → Retrieve → FriendProject.ap12. The project opens in V12.
11. Compile: right-click PLC_1 → Compile → Software (rebuild all blocks). Any block that fails to compile is a V13-only feature; rewrite it in V12 syntax.
12. Save and proceed with your work.

9. Online Connection Problems After Downgrade

Even after a clean downgrade, you may not be able to go online with the S7-1217C from STEP 7 Basic V12 SP1. The Online → Accessible nodes scan returns nothing, or returns the CPU with a red icon and a message "Online: The firmware version is not supported by this version of STEP 7."

Root cause and remedy by symptom:

10. Troubleshooting Matrix

11. Verification Checklist

After completing the downgrade workflow, run through this verification list before signing the project off.

1. Archive round-trip: The .ap12 archive opens in V12 SP1 with no error dialog. Pass = clean open.
2. Block compile: Compile → Software (rebuild all blocks) returns 0 errors, 0 warnings. Pass = clean compile.
3. Hardware configuration compile: Right-click the PLC → Compile → Hardware (rebuild). Pass = no device errors.
4. PLC online accessibility: Online → Accessible nodes lists the S7-1217C with a green check. Pass = online connection.
5. Block compare: Online → Compare offline/online shows no unexpected differences (only the project-level signature differs).
6. Download test: On a non-production S7-1217C, download and run the project. Verify the user program runs in RUN mode with no diagnostic buffer entries.
7. Watch table test: Open the watch table, force a known input, verify the expected output.

12. Frequently Asked Questions