Staying Up to Date
Apple continually produces new and updated help articles, user guides, programming guides, and API references. As updated documentation becomes available, it downloads to Xcode in the background. Be sure to keep your documentation up to date by leaving the default download behavior intact or by manually checking for documentation updates on a regular basis.
Documentation is installed in the form of documentation sets, also called doc sets. Apple doc sets associated with your projects’ SDKs are installed with Xcode, and access to updates for them is controlled by subscription. For your convenience, Xcode can keep these subscriptions up to date. This feature is controlled by the option “Check for and install updates automatically,” which you can select in the Downloads pane (available by choosing Xcode > Preferences).
To check for updates manually, click “Check and Install Now.” If no new updates are available, Xcode displays a message to that effect. When an update for a doc set is available but not yet installed on your system, Xcode displays a Download button on the subscription line for that doc set. Click the Download button () to download and install the updated doc set on your system.