dzBdsLauncher
smart launcher that automatically selects the correct BDS version
...If you open a Delphi 2007 .dproj file with Delphi 10, it will automatically convert it to the new format used by that version and it will be unreadable by Delphi 2007.
The idea is to register dzBdsLauncher as the handler for .dpr, .dproj, .bdsproj, .dof and .groupproj files in Windows, so your chances of opening the right version of Delphi when double clicking on such a file will be much higher than normal.