In addition to watchOS 3, updated tvOS, macOS Sierra, Apple also introduced the biggest release ever to iOS the new iOS 10 at WWDC 2016. iOS 10 brings host of new features including animation, stickers to Messages, ability for Siri to do more working with apps, redesigns Maps, Photos, Apple Music and News app. It also bring a new app called Home, that lets you manage home automation products.

Messages 
You can now send message with animations such as balloons, confetti  or fireworks, invisible ink to friends. To read messages with invisible inks user have to swipe over it. Other features include Automatic suggestion to replace word with emoji, Tapback to create quick & simple respond and Rich links to see content inline & play media without leaving the conversation. iOS 10 also brings App Store to Messages and developers can create stickers, GIFs and more for iMessage, so that users will not have to leave the app.

Siri opens to Developers
Siri is now available for developers for use in third-party apps. Through a project called SiriKit, developers can design their app to work with Siri for messaging, phone calls, photo search, ride booking, personal payments, workouts and other content-based interaction through third-party apps.

Redesigned Maps
Maps has received a new design making it even simpler to use. It is also more smarter and can offer direction to where you most likely want to go next, based on your routine or appointments on your calendar. Along the routes, Maps can suggest you nearby gas station, restaurants, coffee shops and more and provide estimates, how the stop will impact the length of trip. Apple is also opening the Maps app to developer so that they can integrate their apps into Maps app.

Photos app gets Memories feature
This feature uses advanced computer video to help you rediscover favorite and forgotten occasion from the photo library by automatically surfacing them as memories, a feature that is already available on Google Photos and Facebook. Memories also include a edited movie that will show you slideshow of the photos with theme music, titles and transitions.

Home App for simpler home automation
It is an IoT (Internet of Thing) centric app that lets you manage and control smart home appliances from your iPhone. The accessories (camera, door locks, light) can be managed individually or can be grouped into scenes so the work together and with a single command can be controlled by Siri. They can be managed remotely or set up for home automation with Apple TV. 

Redesigned Apple Music
As expected Apple Music gets a revamp, bringing simplicity and clarity to every aspect of the experience including the Library, For You, Browse, Radio and Search. With the new design language, navigation and discovering music is easier.

Redesigned News app
The New app gets a For You tab, that is organized into various section that makes it easier to find stories, support for breaking news notifications and paid subscriptions.

iOS Experience
These include features like 'Rise to Wake' that automatically wakes the screen when you raise your iPhone, making it easier to view all notification at a glace from the lock screen. Notifications, Today view and Control Center are accessible with just a swipe or a press, and deeper 3D Touch integration with iPhone 6s and iPhone 6s Plus makes interacting with apps even easier.

Other features

• Siri intelligence bring QuickType features such as contextual predictions to offer relevant information based on location, calendar, availability or contacts; and predictive typing supports multiple languages without switching keyboard 
• Phone app adds integration for third-party VoIP calls, voicemail transcription and a new caller ID extension for spam alerts. 
• Built-in app updates include Safari split-view for iPad, Notes collaboration and Live Photos editing. 
• Apple Pay can now be used to make easy, secure, and private purchases on participating websites using Safari, in addition to paying in-stores and within apps. 
• Bedtime Alarm in the Clock app lets you set a regular sleep schedule and receive bedtime reminders.

The developer preview of iOS 10 is now available to iOS Developer Program members at developer.apple.com starting today, and a public beta program will be available to iOS users in July at beta.apple.com. iOS 10 will be available this fall for iPhone 5 and later, all iPad Air and iPad Pro models, iPad 4th generation, iPad mini 2 and later, and iPod touch 6th generation.