You can change the default app Settings > System > Default apps > Choose default apps by file type (on the bottom) for each extension, including .ics. I could see in the list The Calendar Windows App, and managed to open an .ics I had received.
You can change the default app Settings > System > Default apps > Choose default apps by file type (on the bottom) for each extension, including .ics. I could see in the list The Calendar Windows App, and managed to open an .ics I had received.