Deleting Old Files After Upgrades

[linux4me]

I've gotten into the habit of going through WHMCS after a major upgrade (like the 7.7.1 -> 7.8.0 I just did) to delete the old files that are left behind by the automated upgrade process. In the past, I've had a couple of issues with files that were left behind, and I think it's a good idea from a disk-space and security perspective not to leave the old files behind.

It's easy to compare the files from a download of the full package with the old files, but I've got a WHMCS license through my web host, and they no longer make the files available for download. The best advice they can give me is to wait until Softaculous has v. 7.8.0 of WHMCS, then install it on a site and compare the files that way. I don't have Softaculous installed on my server, and don't want it, so that's not a viable option.

Looking through the files in my freshly upgraded 7.8.0 install, I see that nearly all of them show today's date when I did the upgrade, so I suspect that the ones that don't have today's date are old files I can remove since I don't have any custom templates or plugins installed. Is it true that the automatic upgrade replaces all necessary files and the ones with old dates are safe to delete?

[linux4me]

I finally decided to pay for a subscription rather than using the free one through my host since they have no means of providing the full download and no plans to provide it.

Once I downloaded the full installation and was able to do a comparison between the new version and the old one, I found that for the most part, it is safe to delete the files older than the date you run the update, with a few obvious exceptions, like your configuration files and any modified templates. Looking over the differences, I wouldn't risk piping the find command to delete them. It seems a lot safer to go through them and make sure something important wouldn't get deleted. There were a lot of files in my installation that are no longer needed. Some dated back to 2016.