This post has good news and bad news on installers for macOS.
The good news is that configuration update installers from version 3.19.0 on are now signed and notarized so you can download and run them without seeing any warning messages.
The bad news is that notarizing is no longer possible for the full installers. We use version 8.2 of the XMLmind XML Editor which was produced many years ago. Apple no longer will notarize it. Therefore we have chosen to use version 3.18.0 of the full installer for macOS from now on. This is not signed and not notarized, but there are ways to get around the warning messages. See the instructions at https://software.sil.org/xlingpaper/download/#mac. Once you do these steps, you can then get the latest configuration update installer and run it.