What Is New in Android 5.1
Android 5.1 Lollipop is a refinement of the 5.0 release, focusing on stability, user experience, and critical system improvements. It introduced several key features that became fundamental to the platform.
| Category | Key Changes |
|---|---|
| New Features | Device Protection, HD Voice calls, Dual-SIM support |
| System UI & Interaction | Quick Settings access, Interruptions & Downtime controls |
| Platform & API | android.app.usage API, Camera2 improvements |
| Security | Enhanced Device Protection security feature |
What security feature made Android 5.1 a must-have update?
Device Protection was the headline security feature. It prevents a device from being used after a factory reset unless the original owner's Google credentials are entered.
This was a game-changer for device theft. A stolen phone became significantly less valuable because thieves couldn't just wipe it and resell it. In practice, this feature dramatically increased the chances of recovering a lost device.
How did Android 5.1 improve communication features?
This update brought official platform support for Dual-SIM functionality and HD Voice calls. For markets where multiple carriers are common, native Dual-SIM support was a huge deal.
Manufacturers no longer needed heavily customized software for dual-SIM devices. HD Voice, also known as VoLTE, provided clearer call quality over LTE networks, moving away from legacy circuit-switched calls.
What changes were made to the Quick Settings panel?
Android 5.1 made accessing Wi-Fi and Bluetooth controls much faster. Users could finally tap the icons in the Quick Settings panel to directly toggle their states, instead of being taken to the full Settings screen.
A long press on the icon would still open the detailed settings. This small but impactful change streamlined a common user interaction, making the toggle system feel more intuitive and responsive.
How did Interruptions and Downtime get better?
The system for managing notifications was refined with more granular control. The "None", "Priority", and "All" modes were supplemented with a new "Downtime" scheduling feature.
Users could set a schedule for when Priority mode would automatically activate, like during sleep hours. This allowed for better automation of notification filtering without requiring manual changes throughout the day.
Were there any important API additions for developers?
Yes, the android.app.usage API was a significant addition. It provided developers with a standardized way to access historical application usage statistics.
Before this, getting app usage data was inconsistent. This API allowed for building better task managers, parental controls, and analytics tools directly into third-party applications with system-level data.
FAQ
Does Device Protection work if the device is offline?
Yes, that's the point. The security challenge appears after a factory reset, regardless of network connectivity. It requires the last synced Google account credentials, making it effective even without an immediate internet connection.
Is the Dual-SIM API available to all apps?
No, the platform support for multiple SIMs was primarily for system-level and telephony services. Third-party app access to manage SIMs is restricted and requires specific permissions granted by the user.
Can I use the android.app.usage API to get real-time usage?
The API is designed for historical usage statistics, not real-time monitoring. It provides data about which apps were used and for how long over the past days or weeks, subject to privacy constraints and user permission.
Did Android 5.1 change how permissions work?
No, the runtime permission model that developers know today was introduced in Android 6.0 (Marshmallow). Android 5.1 still used the install-time permission system where all permissions were granted at once when the user installed the app.
Were there any Camera API updates in 5.1?
Android 5.1 included under-the-hood improvements to the Camera2 API, enhancing its stability and performance on supported hardware. However, it did not introduce major new camera features compared to the initial Camera2 release in 5.0.