Thankfully, there aren't many changes to settings.js that matter if they are missing so using an old version is often not an issue.
Personally there are two things I do.
Firstly, whenever there is a new version of Node-RED, I use VScode to compare the new version of the master file with my custom version to see if anything has materially changed. If it has, then I update my copy accordingly. I do this on my dev machine first and then update other instances.
Unfortunately, this is all manual.
Secondly, if making more complex changes to settings.js, I will tend to use an external module file that is require'd into settings.js so that I keep the custom code seperate.
This is certainly an area of Node-RED that would benefit from some re-engineering when time permits. I know that Nick wants to look at this file.
