I tried first to rename the airports, but the software will only accept the ICAO designator - not a C before or anything to separate it.
I have understood that the new version will come with an import function. I plan to import some information but it will be difficult not to end up with some duplicates. Would it not be an idea either to present the duplicate error on activation of the map or to add a letter to all the custom data, so it does not interfere with the Skydemon official data?
I must admit I don't understand the problem here; once SkyDemon release full or limited charts for a country, you would therefore no longer need any of your own custom airport data for that country, at least not for the public airports that will be covered by our own data and will include ICAO identifiers.