Updating from macOS High Sierra (10.13.6) to macOS Catalina (10.15) is a significant jump that introduces new features like dedicated Music, TV, and Podcasts apps, but also marks the end of support for . 1. Check Hardware Compatibility
Upon booting into Catalina, you will notice major changes: how to update macos high sierra 10136 to 1015
Try each app you rely on: