Re: What happens to customisations after upgrades?
Apologies for the delay in responding to this. Generally when a new release comes out, users are instructed to rename the original CP theme folder and replace it with the new one. Obviously in this instance you would to lose any customizations you have made, hence some other method is needed. With each release, the changelog will generally indicate which files and lines of code are effected, however depending on the complexity of some of the changes, it may not always be possible to give every line changed.
I will try and get some comment from the developer on this particular line of questioning, as I know this is something many would like some info on.