Behind the scenes: a summary of changes in macOS Sierra

Self promotion requires a fine balance: get too gobby and you just look silly; understate and you underwhelm. It is even tougher when you are promoting something that no one else has seen (yet), to several different audiences, from unrepentant nerds to press critics. Apple’s WWDC Keynote calls for all that, and the theatrical skills of someone like Steve Jobs.

So what was covered in this week’s keynote about macOS Sierra has been carefully filtered, massaged, and staged. In this article I am going to trawl a bit more through Apple’s technical documentation, trying to interpret what we can look forward to this autumn/fall when Sierra is released. I have already looked at some of the security issues here.

Apple’s site previews features which were shown in the Keynote, such as Siri, object recognition in Photos, Memories, the Universal Clipboard operating across macOS and iOS, iCloud Drive, Optimised Storage with iCloud, and Picture in Picture.

Apple Pay

Most of us already have bank cards, and continue to use them even though we may now have Apple Pay set up on our iPhone. Cards can be much more of a problem when used online, though, and Sierra’s support for Apple Pay on websites could be a major step forward for online purchases. Developers get a proper JavaScript framework, so you can expect this to be widely supported when it arrives. Note that this allows you to authorise payments using your iPhone or  watch.

Wide Colour

Previously, support for very wide colour gamuts has been patchy, and this has been reflected in varying degrees of support in apps. Sierra extends this through the entire graphics support software, so you can expect wide colour support to appear in all apps for which it is relevant, and its support should be far more consistent at last. Digital photographers should find this a significant improvement.


In addition to object recognition and Memories, photo editing app extensions for Photos can offer live photo editing to both still and video content.

iCloud for all

Support for iCloud across apps has also been patchy and inconsistent. Most of Apple’s apps were given much better support than third-party products, then it was confined to App Store apps, and even there has not been as well used as it should. Sierra extends this, including features to support sharing within a user’s private database. This should allow many more apps to make better use of iCloud, and your iOS and macOS devices to integrate much more.

Console and logs

Not known for its glamour, Apple has recognised that macOS logs have become a jungle, as I wrote here. Sierra changes this in two ways. First, it provides developers with multiple logging levels, and various features which will help them during development, testing, and responding to issues in their products. Messages are to be stored as unified data rather than text-based log files, and a new version of Console will provide improved features to help us wade through logs.

As someone who seems to spend quite a bit of time reading the logs of others, when trying to solve their problems for MacFormat, this should make my life a lot easier. It may also help others understand their logs better.

Safari app extensions

This could be a major new opportunity for developers, as Sierra’s Safari supports app extensions, which extend the behaviour and facilities of Safari. These are much more than its current plug-in extensions, and will perhaps bring more sophisticated content blockers to desktop Macs too. These may well have to be distributed via the App Store.

Smart card and  watch authentication

Sierra will support Smart card drivers, and the watch, as authentication through the normal keychain mechanism. So far, authentication methods other than password entry have been little-used with Macs (except in some specialist enterprise systems), and this may help us move away from the many problems of passwords, without having to scan irises, etc. However, this support does not include writing to Smart cards: it is intended for authentication, not Smart card configuration.

AI and maths

Sierra includes specially accelerated support for integral calculus, in maths, and the construction of neural networks, in Artificial Intelligence. At this stage it is not easy to envisage what apps might do with those features, but they could be used for some seriously exciting purposes in the future.

Unit conversions, dates, and more

It’s amazing how many apps deal with physical units, such as length and temperature. Sierra offers unit conversions for many of these, for dealing with dates including date intervals, and personal names. These should help standardise these small but important details across many different apps.


The Game Center app is removed from Sierra, but support is added for iCloud game accounts.

There are a lot of enhancements to the rendering of 3D objects, which should improve games and apps which work with 3D objects. Specifically, Sierra introduces a new Physically-Based Rendering (PBR) system based on recent graphics research, with enhanced shading, lighting, HDR rendering, and improved colour accuracy. These should enhance not just those apps written specifically to use these new features, but existing apps which use Apple’s current interfaces.

The passing of HFS

Sierra does not, of course, introduce Apple’s new file system APFS, which will not become a feature of macOS until next year. However, Sierra does finally discontinue support for the early version of the current HFS+ file system, HFS. If you’re still using HFS, you have a bit of catching up to do!