4D Server and 4D Client downloads are individual folders which contain all of the necessary items to run the respective application. You can replace the old 4D Server or 4D Client folder with the new one if you wish. No other files or system modifications (like registry edits for example) are necessary.

When upgrading 4D Client and 4D Server applications to version 6.7.1, you will also want to download the 6.7.1 version of the network components.

https://www.4d.com/downloads/aciprod.html

Remove and replace the old network components with new network components on both the server and client machines. Network components go in the active windows directory.

Under Windows NT/2000----> C:/WinNT/4D/Network

Under Windows 95/98/Me---> C:/Windows/4D/Network

After the network components are replaced, launch 4D Server 6.7.1 and choose the appropriate database. For 4D Client 6.7.1, simply launch 4D Client 6.7.1 and choose the appropriate server.