Siemens WinCC (TIA Portal) V11 and later. The last version that could directly open WinCC Flexible 2007 projects without major conversion was TIA Portal V13.
: Available in Micro, Compact, Standard, and Advanced versions to support different HMI hardware complexities. siemens wincc flexible 2007 download
If you need the software for legitimate maintenance of existing equipment, here are your options: Siemens WinCC (TIA Portal) V11 and later