Making Backups Before Replacing Files
Inno Setup does not currently have a specific feature for doing that, but you can make a copy of a file before it is replaced by using a [Files] section entry similar to this:
Source: "{app}\MyProg.exe"; DestDir: "{app}\backup"; Flags: external skipifsourcedoesntexist uninsneveruninstall
Pedro Silva
world is wonderful with your help .