If you use Apple's CarPlay functionality you'll probably want to install the iOS 10.3.3 update on your device.
If you failed to install iOS 10.3, iOS 10.3.1, or iOS 10.3.2, your iOS 10.3.3 update comes with some major changes to the service.
On older versions of iOS software, CarPlay required you to make multiple taps to access another application. You'd be forced to tap Home and then make another tap to open up a new application. That changed with the release of iOS 10.3.
Apple's eliminated the need for a second tap. Now you'll notice three applications sitting in a dock aligned on the left side of the screen. These are static and they'll stay in view when you're inside other apps.
A majority of the time you'll see Maps, one of your entertainment applications like Spotify or Music, and an app for communication purposes (Phone, Messages, Skype, etc).
iOS 10.3.3 also brings daily curated playlists, new music categories in Apple Music, an Up Next function in the Now Playing screen inside the Music app that allows you to easily skip around tracks in a playlist, and the ability to tap an album title from the Now Playing screen so you can easily jump to the song's root album.