🌙 Background Modes

Entitlements that let your app keep working when not foregrounded: audio (music/podcast playback), location (turn-by-turn, fitness tracking), fetch / processing (periodic refresh via BGTaskScheduler), remote-notification (silent pushes), voip, bluetooth-central, external-accessory. Declared under UIBackgroundModes in Info.plist.

Only when a user-visible feature genuinely needs it: a run tracker needs background location; a player needs background audio. iOS aggressively limits background work — fetch/processing run at the system's discretion, not on your schedule. If you just need 'sync when opened', you don't need any of these.