Scrcpy v4.0 introduces several key enhancements:
- Aspect Ratio Locking: Migration from SDL2 to SDL3 allows native preservation of device aspect ratio when resizing the desktop window, eliminating black borders.
- Dynamic Flex Display: A new feature enables dynamic resizing of virtual Android displays, allowing applications to run in standalone windows for improved multitasking.
- Non-Invasive “Keep Active” Mode: The new “–keep-active” command maintains the phone screen's activity without changing global screen-timeout settings by sending periodic user-activity signals.
- Live Camera Controls: Users can now make real-time adjustments to hardware settings like flash and zoom when using their phones as webcams or streaming camera feeds.
- Improved Disconnection Alerts: A clear “disconnected” icon is displayed for two seconds before the scrcpy window closes after a dropped connection, providing better feedback.