Xcode is the complete developer toolset used to create apps for Apple TV, Apple Watch, iPad, iPhone, and Mac. The Xcode development environment bundles the Instruments analysis tool, Simulator, and the OS frameworks in the form of tvOS SDKs, watchOS SDKs, iOS SDKs, and macOS SDKs.

Swift 3

Xcode 8 supports Swift 3 as well as Swift 2.3. A Swift migrator is provided to help upgrade your Swift code to the latest Swift 3 language specifications and SDK requirements.

All projects created with Xcode 8 use by default Swift 3. You can use legacy swift language version (Swift 2.3).

Signing

Now Xcode can manage signing for you automatically. Xcode will automatically create and update profiles, app IDs, and certificates. Every project created with Xcode by default enable automatically signing.

Interface Builder

Xcode have new adaptive UI development tools and workflow.
Image Source - Apple

Source Editor

Source Editor Extensions - Now you can created native Xcode source editor extension. Xcode 8 have native template to builds an Xcode Source Editor that allow you to add commands to interact with the Xcode source editor.

Code completion for images - Xcode 8 have native support for image name completion.

Jump Bar - Clicking the Jump Bar, located at the top of every editor pane, you can quickly select what information to view in the Assistant editor.

Debugging

Memory Debugging - Xcode 8 also have memory debugging feature which show how memory assigning to every object with a nice graphical representation.

Runtime issues - while debugging appear in the issue navigator, similar to compile-time issues:

  • Leaks issues identify potential leaked memory detected during debugging sessions.
  • Thread sanitizer issues identify threading-created race conditions on data changes at runtime.
  • View debugging issues identify constraints conflicts.

Documentation

The new documentation format looks gorgeous and the documentation browser is fast and easy to use.