MacOS High Sierra

macOS High Sierra, or macOS 10.13, is a version of macOS developed by Apple, which was released on 25 September 2017. This version introduces various changes to core macOS components, including a new filesystem (APFS) designed to replace the older HFS+ filesystem used since Mac OS 8.1. This version also introduced separate updates (BridgeOS) for the ARM co-processor included in certain Macs.

New features and changes

 * APFS is a new filesystem that replaces HFS+ and uses Copy-on-Write, containers, and encryption to increase performance on SSDs.
 * A new Metal API, including additional support for VR headsets and external GPUs.
 * New privacy tools in Safari, including Intelligent Tracking Prevention.
 * The Photos app has been updated with new editing tools and UI adjustments.
 * 10.13.5 adds iCloud support to Messages.
 * Siri voices have been updated to be more natural.
 * Tables can now be added in the Notes app.
 * New H.265 (HEVC) decoder service (with additional hardware acceleration on certain Macs).
 * New HEIF decoder service for HEIC-formatted images.
 * Support for FLAC and Ambisonics file formats.
 * Swift 4 support (in Xcode 9).
 * Support for T2 chips.