First, minimal test ISO is uploaded for the June 2016 KaOS stable ISO.

As always, early test ISOs are minimal, no language packs (though Plasma 5, just the desktop, has the translations build-in), very few apps, just a web-browser, file manager, text editor, GUI package manager. The non-free nvidia drivers are included since they are a big part of what needs testing.
This is a first ISO with a complete revamped way for (early) microcode loading, to check if your system did get a microcode update, run

dmesg | grep microcode

both in Live mode and (if you should install) installed system.

KaOS ISOs are not only GTK free but from now on Qt4 & KDE 4 free too.
This is as pure a Qt 5/Plasma 5 ISO as possible.

Plan is to have Frameworks 5.23.0, KDE Applications 16.04.2, Plasma 5.6.95 and Linux 4.6.x on the final ISO. If all testing goes well expect the final ISO around the third week of June. If testing goes smooth Plasma 5.7 won't be final, thus 5.6.95 will be used.

Calamares version used is 2.2.93. It is now build with LUKS support, this is still in an early stage, thorough testing will be needed. Release Notes page is not updated yet, you will see the text from the April ISO. Calamares now fully supports NVME drives, would be nice if anyone with such a new ssd could test.....

This ISO is build with Qt 5.7RC, new kernel 4.6.2 from the build repo and all applications in the kde-next repo. And the usual updates to packages since the last ISO are in the hundreds.

The ISO is using packages from the build & kde-next repo, but those repos are not enabled, so if you decide to install, make sure to add those repos to your pacman.conf.

To help with testing:

Use in live mode on as much different hardware as possible
If you have an UEFI capable system, check if the ISO boots in both UEFI and legacy BIOS mode, make sure though to turn off secure boot
test installs on real hardware are needed, not just vbox
check as many partitioning options as possible in the all new partitioning of Calamares, see if all works and is clear enough

debug packages for Calamares are part of all ISOs from now on, run Calamares with gdb if you encounter errors
provide the installation log, if you encounter any issue at all

You can start Calamares from the Welcome app, or run it with:

sudo calamares -d

The install log will be created in the home directory of the Live user, see ~/installation.log. It is available after the install in the target system in /var/log/installation.log

Test ISO is NOT up at the usual place, DistroWatch decided with a previous release cycle to make these test ISOs (which are not intended for public use) public on their website, having it look like they are stable releases. Therefore a new site is used from now on for these test ISOs:
http://kaosx.tk/repo/KaOS-2016.06.11-x86_64.iso
https://sourceforge.net/projects/kaos-test/files/iso/KaOS-2016.06.11-x86_64.iso

On this ISO you will find:
Linux 4.6.2
systemd 230
gcc 4.9.3
Qt 5.7RC
Frameworks 5.23.0
Plasma 5.6.4
KDE Applications 16.04.2 kf5 based
Git builds of KDE Application that are ported to frameworks, but were not part yet of 16.04
Calamares 2.2.93
Octopi 0.9dev with sysinfo & cachecleaner tool

Known issues:

The welcome app link to the forum still points to old url, issue fixed in git
Latest QtCurve is not stable, causes segfaults in kactivitymanagerd in Live, new version is up in [build]
Launcher script for Calamares wrongly uses on 'or' statement, thus never showing the License Page/installing non-free Nvidia, fixed in git