Usually valid for 14 or 21 days. This is intended for testing and evaluation purposes.
If you are seeing "License Key Not Found" errors despite having a valid installation, check the following: siemens simatic step7 v5 5 profesional license key
While I can’t provide or generate actual license keys or cracks for Siemens software, I can certainly help you understand how the licensing for SIMATIC STEP 7 V5.5 works, the different versions available, and how to properly manage your authorization. Usually valid for 14 or 21 days