Hopefully the evolution doesn't break the audio again.. Luckily there STILL isn't a hardware refresh on MacBook Pros yet, which means we still aren't prevented from using Yosemite. By the time Sierra drops that will probably change.

Only those with 2010 or newer MacBook Pro's that is.....................

So, did somebody already try new system with SeratoDJ ?

it's only available to developers at the moment which I'm sure there are others in here too but I'll be trying it out on a partition on my machines soon

Yes, it will be compatible.
Just don't ask when it will be ready. It will be ready when it is ready.

I'm more interested in the new file system!

If macOS Sierra follows the same release schedule that OS X El Capitan did, it will be released at the end of September. The beta of Sierra is currently only available to developers, with a public beta coming sometime in July. (source: www.macrumors.com)

Apple also (quietly) announced their new file system, Apple File System (APFS), which will replace the HFS+ file system that Apple has used for the past 30 years. It is described as being optimized for solid-state drives and flash storage, and focuses on encryption. APFS is scheduled for a 2017 release. You will most likely need the latest version of macOS to use this new file system, as APFS formatted volumes are not recognized on OS X 10.11 Yosemite and earlier. (source: 9to5mac.com)

I'm sure we're all hoping that the upgrade process to macOS Sierra will be a better experience than the El Capitan upgrade.

I am running OS Sierra, Serato DJ 1.9.3, and the Rane SL2 with Tech 1200s. No issues through about 4 hours of testing.