Google released Android 5.0 Lollipopback in November of 2014 with a complete UI revamp and a number of cool new features like Smart Lock and priority notifications. After an initial burst of device updates, things slowed to a crawl as a number of bugs popped up that needed attention. Now Google has announced Android 5.1 Lollipop with a handful of notable features and (presumably) important bug fixes. You probably won’t see it on your device for a long time, though.

Android 5.1 was previously only available on Android One devices in The Philippines and a few other emerging markets. Its existence was kind of an open secret, as Google refused to officially acknowledge the new version existed — even going to far as to scrub any mention of it from the Android One website. Now that the rollout is underway, Google is coughing up the details on what’s new.

Android 5.1 will include three significant new features — dual-SIM support, native HD voice, and Device Protection. The dual-SIM features pertain mostly to Android One phones, all of which have two SIM slots. There were dual-SIM phones before, of course, but the software support for that was always a custom job by the OEM. HD voice support means all Android 5.1 devices will support the voice features of VoLTE going forward as well. This opens the door for Verizon to finally start selling the Nexus 6 in its stores.

The new Device Protection feature is an interesting one. According to Google, Device Protection will be able to lock down your phone or tablet in the event that it’s lost or stolen. The only way to unlock it is to use your Google account password. This goes beyond existing tools like the Android Device Manager, because Device Protection works even if someone resets a stolen device to factory defaults. This is probably a reaction to laws being passed in a number of US states that require a “kill switch” in mobile devices to deter theft.

Device Protection will only be available on phones and tablets that ship with Android 5.1, plus the Nexus 6 and Nexus 9 after the 5.1 update. That means the big new 2014 flagship devices like the Samsung Galaxy S6 and HTC One M9 won’t have Device Protection, as they will ship with a build of Android 5.0.

Android 5.1 likely has fixes for some of Lollipop’s more annoying bugs, like the memory leak that causes apps to close in the background and random Wi-Fi disconnect issues. These bugs were listed in the Android public issue tracker as fixed and scheduled for a future release, so hopefully this is it.

The rollout is starting today, which means OTA updates are going out to Nexus devices. This will be followed by full factory images for these phones and tablets, which can be used to flash them back to stock after modifications. This process will probably be complete in a few days, but from there the wait gets much longer. Device makers will have to take the new code and merge it with their custom Android builds, and then have it certified by carrier partners. That process could take a few months.