Apple today released updated versions of iOS, watchOS, tvOS and iTunes. iTunes 12.4 features a more refined interface with the purpose of making content easier to find. iOS 9.3.2, watchOS 2.1.1, and tvOS 9.2.1 are mainly bug fix updates.
As always, be careful when updating your devices, and make sure you have a good backup. Head over to the update section on your device to download and install the new firmware. Learn more.