SIMATIC 50h Engineering V21 Combo floating license download 50 h usage time for the following SIMATIC engineering software: STEP 7 Professional 2021 SR4, STEP 7 Professional V21, WinCC flexible 2008, WinCC Professional V21, STEP 7 Distributed Safety V5.4, STEP 7 Safety Advanced V21 software, documentation and license key for download -- for system requirements specification, see www.siemens.com/compatool -- software class A -- consignee email address required for delivery.