I have been working on Delphi since 2000( Delphi 1) to now DelphiXE10. I currently have Delphi 7, Delphi 2007 , Delphi Xe2 and Delphi XE10 installed in my system on multiple OS windows 7 and windows10.
I have my own projects that is being used by more then 50 establishment for more then 5 years now.
Lots of client work included installing and recompiling existing application on Delphi for fixing or modifying or extending application.
One of my project was to attend to issues raised by users of an enterprise application , and later on upgrading that application from Delphi 7 to Delphi 2010,