I'm surprised that they even deigned to answer you
Given that the software is now very old and they have no interests or income, it's no wonder they won't develop any add-ons.
And the main thing is that almost none of the skins and add-ons were even developed by NNG itself
In fact, if the internet community was not this strong and there were not this many enthusiasts with adequate knowledge, I think iGO for WinCE although it is extremely functional and usable would have died a long time ago.