It is not possible to run two different versions of STEP 7 with the same operating system on one computer. You must also take into account that an earlier version of STEP 7 is not compatible with the current operating system, or that the current version of STEP 7 is not compatible with the operating system under which the earlier version of STEP 7 is installed. For example, of versions V5.1 and V5.3 of STEP 7 only V5.3 is released for running under Windows XP SP2.
However, if you nevertheless have two versions of STEP 7 installed on different drives on one computer, the following message is displayed when you open the SIMATIC Manager:
- "S7upaapx.exe: cannot find the dynamic link library S7upddlx.dll".
Although the SIMATIC Manager can then be started, we recommend completely deinstalling both versions of STEP 7. Here you must also delete the Registry entries. For this we recommend you refer to the FAQ "Complete deinstallation of STEP 7 including all software packages" in Entry ID: 189025 .
There is an option of installing two operating systems on one computer using a double-boot system. In this way it would be possible to have two different versions of STEP 7 running on one computer. More information about setting up a dual boot system is available in our Entry ID: 18984531.