I'm not sure where to post this question, so General Discussion!

When a game gets updated and I want to get the updates, should I just select to re-download the game, or should I delete/archive the existing version first?

The Witcher got updated recently, so lets use that as an example. Last week I downloaded everything I own here via the GoG downloader. Witcher gets an update today, and I want to capture the update. If I just tell the downloader to download it again (to the same file location), will all file changes (including any files that are removed as part of the update!) be handled correctly?

As an addendum, say that I have the Witcher installed, and an update occurs. To apply the latest update, should I just run the updated installer on top of the existing install, or should I uninstall first and then install the newly updated download?

I really wish the update logs would mentions explicitly both when you have to and when you don't have to uninstall the previous version. That goes doubles for DLC and games that have DLC. I normally uninstall everything and then reinstall everything.

And regarding the OP, it would be nice to know how the GOG client deals with updates. Not knowing is one of the reason I do not use it. Does it remember the versions of the files it has downloaded or does it check what has been downloaded every time? It's important for me because I do not keep my GOG archive on a local drive.

It checks if you already have the file you want to download if you are always using the same folder for downloading the games. So no the downloader does not remember, if you use a different download location it can not check and will just download again.

So if a file were deleted (maybe a programmer realized that "Hall-Of-Fame.ini" should be "Hall-Of-Fame.txt"), the downloader will remove the deleted file as part of downloading updates?

I'm hoping this is the case, since it would make life easier for the customer (which GoG is pretty good about, in my experience).

Since the downloads are installer files, so only one .exe file the downloader can't do anything like this, it is just for downlading the installer or the patch. But probably when updating, the installation should be changed to have a correct version after with all needed and without unnecessary files.

I hadn't looked closely at the folders for any games with no extras, so I always saw a bunch of files. Your answer sounds about right, though.

Also, I think I just found the proper channel to ask GoG directly; I'll post here once I get a reply (assuming they don't answer here directly).