Now you can unlock your iPhone with a mask on. Better late than never.

IOS 15.4 and iPadOS 15.4 updates pack a handful of notable features and security tweaks for your devices. Apple devices as old as the iPhone 6s (released in the fall of 2015) can run iOS 15.4, while most iPad models from late 2014 onward can install the corresponding iPadOS update.

These updates include long-awaited additions, such as the ability to unlock your iPhone with your face even while wearing a mask. Another new feature, Universal Control, lets you interact with your nearby iPad while you're sitting at your desk with a Mac. And because words hardly seem like enough anymore, we now have a bevy of new emoji at our disposal.

Let's be clear: Whether you plan to use any of the company's new features or not, it's worth keeping your devices' software up to date to dodge potential security issues. Here are the some of the most useful features found in iOS and iPadOS 15.4, and what they mean for the way you use your devices.

Face ID now plays nice with masks

Considering that mask mandates across many parts of the United States are being lifted, Apple was perhaps a little late with this feature. Since we're still in the midst of the pandemic, though, covid-cautious users can still get plenty of mileage out of it. (That is, if they're using fairly new iPhones - this addition only works on the iPhone 12 series and newer.)

Even if you've set up Face ID ages ago, you'll be asked to enroll your face in Face ID again once you've installed the update. Why? So your phone can get a better look at your eyes - as well as the space around them. If you opt into using Face ID while masked, Apple says the feature will attempt to "recognize the unique features around the eye area" to determine that you are, in fact, you.

Once you've made it through the setup process, Face ID should work as it does when you're unmasked.

Still, these speedy unlocks can come at a cost. Apple admits that Face ID is most accurate when it can look at your whole face, so don't be surprised if your phone occasionally flubs an unlock while you're masked. That's especially true if you wear hats such as toques and beanies that cover additional parts of your face, and sunglasses in particular are a no-go. (Regular glasses are fine, though.)

While these mask tweaks make Face ID less secure in some ways, it's (thankfully) still not that easy to trick - you can't, for example, point your phone's front camera at a video of yourself wearing a mask and unlock it.

Interact with your iPad from your Mac

Universal Control, a feature that will let you control multiple Apple devices at once, might be the most anticipated addition in these updates. (That's because it was originally meant to launch last year, around the time iOS 15 and iPadOS 15 were released.)

Let's say you're working on a Mac and your iPad is propped up next to it - once both of them are running the latest software, you can move your mouse's cursor between those screens to move files around or copy and paste text more easily.

The simplest way to get this kind of connection going is to connect the iPad to your Mac with a USB cable, though getting those devices talking to each other wireless is pretty straightforward. Just make sure both of them are signed into the same iCloud account and have Bluetooth, WiFi, and Handoff enabled.

The one catch? You'll need some pretty recent hardware to pull this feat off. The full list of compatible devices is here, but just know you're out of luck if you bought your iPad before 2018 and your Mac earlier than the end of 2015.

What else is new?

- AirTag tweaks: IOS 15.4 packs a few changes to the way Apple's potentially creepy trackers work. Among other things, the update includes better recognition for nearby AirPods, so they won't prompt a concerning "unknown accessory detected" warning, and the ability to use the Find My feature on newer iPhones to lead you to AirTags placed around you. (Previously, you could do this only for AirTags you owned and set up.)

- Siri gets a new voice: Voice assistants are powered by machine learning models and sophisticated algorithms, so why do they need gendered voices? Enter Siri's latest voice option - American Siri Voice 5, for those on the hunt - which isn't distinctively male or female.

- Emergency call behavior changes: Hopefully, you've never had to use the iPhone's "click the power button five times" trick to call emergency services. If you have, iOS 15.4 may require you to turn it on again - it was once turned on by default but now seems optional. (That said, the Call to Hold feature that triggers a call to emergency services when you hold down the power and volume buttons is on by default.)

- New emoji: Apple added dozens of new emoji to iPhones and iPads with these updates, including a saluting gesture, a bitten lip and, uh, some beans. Knock yourself out.

- New ways to tap and pay: Deep inside iOS 15.4s code is a feature that allows business owners who use payment processors such as Stripe to accept mobile payments with an app running on an iPhone XS or newer. What does that mean? At some point this year, you'll be able to pay some businesses by tapping your phone or contactless credit card to their iPhone.

What isn't in this update?

There's at least one feature Apple has teased in the past that hasn't turned on yet: support for digital driver's licenses. The company first announced the feature last summer during its Worldwide Developers Conference, and originally said it would be available in late 2021 before pushing the launch to "early 2022."

Should I update now or wait?

Updating would be a good idea. Beyond a handful of new features, these updates also frequently come with bug fixes and security patches that could improve the way your phone performs. (To get a sense of the kind of vulnerabilities companies target with new software releases, check out Apple's list of fixes for this update.)

That said, these kinds of updates aren't always free of bugs, so it's a good idea to make a full backup of the data on your iPhone or iPad before installing a big new software release. Here's how to do it.

-Back up your phone to iCloud

1. Open the Settings app

2. Tap on your name at the top of the screen

3. Tap iCloud, then iCloud Backup

4. Tap Back Up Now

-Back up your phone to a Mac

1. Connect your iPhone to your Mac with a USB cable

2. Open the Finder, and click your iPhone's name in the sidebar under "Locations"

3. Select "Back up all of the data on your iPhone to this Mac"

4. Optional: tick the box next to "Encrypt local backup" if you want to make sure your data is unreadable to anyone else

5. Click Back Up Now

-Back up your phone to a PC

1. Connect your iPhone to your PC with a USB cable

2. Open iTunes and look for the iPhone icon in the top left corner

3. Click Summary, then Back Up Now

4. Optional: Tick the box next to "Encrypt local backup" if you want to make sure your data is unreadable to anyone else