It is worth noting that Siemens offers licenses. If you have a STEP 7 V5.5 Professional license, you can often upgrade to a TIA Portal Professional license, which usually includes "Combo" rights—allowing you to run both the modern TIA Portal and the classic V5.5 software with a single key. Important Legal Notice

I expect that this true for V5. 5 too. You do not even have to have the Step7 software installed on you PC to upgrade the license.

Siemens Simatic Step7 V5 5 Profesional License Key

It is worth noting that Siemens offers licenses. If you have a STEP 7 V5.5 Professional license, you can often upgrade to a TIA Portal Professional license, which usually includes "Combo" rights—allowing you to run both the modern TIA Portal and the classic V5.5 software with a single key. Important Legal Notice

I expect that this true for V5. 5 too. You do not even have to have the Step7 software installed on you PC to upgrade the license.