The upgrade process to macOS Big Sur 11.0.1 preserves your custom automount master mapping (auto_master) file. This is a welcome improvement over Catalina, and eliminates the need to manually restore your auto_master customizations after the upgrade.
After upgrading to macOS Catalina 10.15, or installing a subsequent 10.15.x update, the auto_master file will be overwritten. You may need to re-append any custom lines to auto_master after the upgrade to restore your previously-working automounts.
After upgrading to macOS Catalina 10.15, your previously working autofs mountpoints may need to be updated with Catalina’s new filesystem structure.
