It might not appear to be the biggest update in recent memory, but Google's Android 5.1 is actually pretty substantial. The arrival of Lollipop late last year was a big shift for the platform, and easily the best and most beautiful version we've seen to date. But it wasn't without its problems—some of them pretty major, too.

That's where last week's update comes into play. Most of the changes occur under the hood, meant to squash bugs and introduce other backend enhancements. But we've also discovered some other stuff worth mentioning

If you haven't yet received the update on your Nexus device, we have you covered. Google's rollouts typically take a few weeks, but there's nothing wrong with getting impatient. We've been using the Android 5.1 update on both the Nexus 5 and Nexus 6, and can say without hesitation that it's definitely worth it. Not only has battery life noticeably improved, but the software is just faster overall. And, no, we haven't noticed any issues on the Nexus 5, but that's something to keep an eye on.

When Google detailed Android 5.1 earlier this month, the search giant mostly glossed over a lot of great features that were added. Some of the bigger ticket items include support for multiple SIM cards, Device Protection and HD voice on compatible phones. But there were other enhancements, too, like system volume tweaks, some new animations, and many more, which you can see in the very, very, very long changelog.

Below we have it broken up by big changes and small changes. If you want to see the update in action, check out the video above.

Big Changes 

  • Quick Settings — Wi-Fi & Bluetooth Quick Access buttons. Click on the Wi-Fi drop down button. It now shows a mini menu with different Wi-Fi connections inside quick settings. Same goes for bluetooth. No need to hit the settings app to connect.

  • Change system volume while audio/video is playing

  • Swiping up a notification won't dismiss it, but keep it for later. Before if a notification was swiped away, it would disappear from the notification tray.

  • Android now recognizes Wi-Fi connections with no internet access and won't automatically reconnect. 

  • HD Voice support for T-Mobile or Verizon Nexus 6 devices.

  • Support for two SIM cards (dual-SIM)

  • Anti-Theft Device Protection, which for now is only available for the Nexus 6.  Basically if someone tries to wipe your phone, they'll have to enter the account password of the last Google account on that specific Android device. Device Protection should be enabled automatically.

Small changes

  • New animation for Auto-Rotate/Portrait mode button in quick settings.

  • Screen Pinning now shows which buttons to press to leave screen pinning mode—otherwise works like before

  • Change (system) volume while audio/video is playing. Before you couldn't do that.

  • Also new animations within the clock app.

  • Default Android icons in services/running applications were 3D, and have now changed to a much flatter Material look.

  • Lock screen: subtle change. Swiping outside of QS area will unlock phone rather than swiping QS to see lock screen area.

  • Editing a contact looks much cleaner and simpler now with a few Material Design elements throughout the contacts app—less Holo-inspired elements.