Hot on the heels of yesterday's Android 5.1 Lollipop announcement, Google has released the Android 5.1 SDK to developers, along with details of the dev-facing stuff contained in the new version of the OS. Firstly, Android 5.1 brings the platform up to API level 22, which includes new APIs for devices with more than one SIM, as well as additional APIs for carrier services.
In contrast to the enormous number of new APIs debuting in API level 21 (Android 5.0), API 22 adds only a "small number" of new APIs, according to Google. There's new stuff to help app developers manage network activities on phones with two or more SIM slots — for instance, detecting which SIM is in use, and whether a particular SIM is roaming.
There are also new APIs to allow carrier-developed apps, distributed through Google Play, to perform network provisioning tasks and other functions in the telephony system. Communicating directly with the network interface is now possible via an app with "carrier privileges." Previously only the Android system could do this, and updating these sorts of things often required a firmware update.
This is a step towards pulling network features out of the system and will allow for easier — and hopefully faster — updates in the future.
As Google explains:
These APIs provide a secure and flexible way for carrier-developed apps to perform these tasks and be distributed through Google Play. Apps that use these functions must be signed by a certificate that matches the certificate in the device's Universal Integrated Circuit Card (UICC).
While there's no evidence of a direct link between the two, it's interesting to see this stuff rolling out right as we're expecting the Verizon Nexus 6 to rear its head.
The updated SDK files are available from Google's developer site at the source link. Updates for Nexus tablets from the Nexus 7 (2012) and up, and phones from the Nexus 4 and up, are slated for the "next few weeks."
Source: Android Developers