Amazon and Best Buy are offering the second-generation Moto G and Moto X for $99 and $242.99, respectively. Pictured above: Different colored examples of Motorola's Moto X phones rest on a table at a launch event in New York in 2013. Reuters/Lucas Jackson

The latest Android 5.1 Lollipop update began rolling out for the first generation of Moto X on Saturday. The new firmware is now available for users in the U.S., Canada and Brazil.

The rollout followed a Google+ post earlier this week by David Schuster, Motorola's senior director of software product management, saying that the soak test for Moto X (Gen 1) and Moto X (Gen 2) began on Thursday. He also said that if everything goes according to the plan, “full deployments” should take place sometime next week.

Users should note that the new Android 5.1 Lollipop update is released for retail devices in the U.S. and Brazil and those on Rogers in Canada, while the carrier specific models of Moto X (Gen 1) in the U.S. are expected to receive the update on a later date.

The firmware update includes several bug fixes and notable features, including the new material design and various other key UI enhancements. In addition, users can now manage Wi-Fi and Bluetooth connections directly from the quick settings on the device.

Meanwhile, the Verizon version of the Moto X (Gen 2) is expected to receive a soak test soon, with reports saying that the update is likely to be the Android 5.1 Lollipop. A soak test refers to the testing process over a period of time before the actual release of the firmware for the public.

Here are some important UI changes included in the Android 5.1 build:

  • Notifications will appear on the lockscreen and are intelligently ranked by type and who sent them.
  • Users can double-tap to open one, swipe left or right to clear one, or clear all notifications from the bottom of the list.
  • Users can set the priority and privacy of notifications for each application.
  • Users can block interruptions until the next alarm.
  • Notification volume controls can be altered while media is playing.

More information about the update is available on the official website.