I want to update a Mac Mini 2012 from Sierra to Mojave. I'm sort of reluctant right now since Sierra is my go to OS and have not had any issues. But I want to try. My question is related to the APFS / HFS+ disk format. I know that Mojave requires APFS is required. Will updating automatically modify the disk format of my HFS based Sierra to the required APFS one? I would like to retain my data and specifications as much as possible during this update. Thanks for any recommendations/insights/help.