When installing new version there is information that current software needs to be uninstalled. Uninstallation removes program configuration…
Please:
I know that I can store machine profile, but other settings will be lost. As for now I copy whole .xml file and restore it after updating.
Thanks for mentioning this. There’s always a reason 
Uninstalling makes sure it removes the config file as well; so the ‘new’ program knows for sure it’s clean and the config file is correct.
I did it because sometimes we change the configuration file’s format. I will check what freedom i have here.
I think it should be possible to load a ‘smaller’ configuration file. Honestly i haven’t tried yet; but will put it on top of the list.
Change format? You have XML file - as flexible format as possibile. Honestly - new software should work with it, especially adds new records and previous version (when downgrading because of, ex. errors in new program) should use it as normal (read/write known data, passing other). That’s the point in XML.
Second thing - every program may know from which version is config file. You can save config version in XML file. Of course it depends on used libraries for XML, but it’s best format to NOT have to do things like uninstallations or clean install.
And last - you, as programmer, have to suffer once writing this. Every user has to do it on every installation and every version change. Choose wisely as software creator 
Would have been nice if there were instruction on how to install the update - and then the update destroys our profiles - seriously…….