+ Windows 7 Professional/Enterprise/Ultimate SP 1 (64 Bit) + Windows 7 Professional/Enterprise/Ultimate (64 Bit) + Windows 7 Professional/Enterprise/Ultimate SP 1 (32 Bit) + Windows 7 Professional/Enterprise/Ultimate (32 Bit) Simatic Step 7 Professional V5.5 supports the following operating systems: This is the version used for Windows 32bit (64bit) computers. STEP 7 Professional V5.5 software is Siemens software used to program the S7-300, S7-300 PLC.