This document describes developer-level features that were introduced in different versions of OS X.

This document is not intended as a complete list of features or changes for each new version of OS X. Instead, it focuses on those features or changes that affect the development of third-party software, providing overviews of each along with insight into how and when you might use them to create your own software. Wherever possible, this document also provides links to other Apple conceptual and reference documentation for that feature or change.

For each shipping release, this document also provides links to “delta” reference documents, which list the new and changed programming interfaces that were introduced in that release.

Organization of This Document

This document includes the following articles: