How to create an update installer with NSIS?

Question

Currently I have an installer created using NSIS. Now I want to create an update installer which updates the application to the newer version by copying only the changed files. The target platform is windows.

Answer 1

The question is too broad. It will probably get flagged as invalid. BTW,

• if your installer overwrites all files, it could work as a not-very-clean updater too.
• Ultimately, your installer/updater should check on start, if the program is already installed, and if necessary, uninstall it before installing the new version. I recommend it calls the uninstaller installed by your first installed, and then performs a regular install. You should keep registry records if you want to keep current settings.