What limitations exist regarding the state of Background in systems or applications?

In the background state, iOS applications operate under resource and execution time constraints:

• The app is not visible on the screen and may be suspended by the system to save resources.
• The execution time for background tasks is limited (usually a few seconds) unless special background modes are used.
• Background tasks should be short and efficient; otherwise, the system may terminate the app.
• For long-running background operations, Background Modes (e.g., audio, location, file download) should be used.
• Access to some resources, such as UI elements, is restricted.

Therefore, developers must carefully plan background work to comply with platform rules and ensure good performance.