According to our PC - Windows 10 Insider Preview Build Tracker for 2016 Windows 10 Build 14366 was released to Fast Ring Insiders for testing on 14 June and just three days later was pushed out to the Windows Insider slow ring for further testing.
The pace of fast ring releases has been full of hustle since then with three new builds released to Windows Insiders (14367, 14371 and 14372) so when a slow ring build heads out is an opportunity for a lot of testers to finally see a new build.
Microsoft's standard practice is to only release a downloadable ISO for Windows 10 testing builds once it reaches that slow ring.
This ISO image provides a couple of benefits beyond broadening the testing pool by allowing users in any ring to perform a clean install of Windows 10 or do perform an in place upgrade on systems that can no longer see the updated builds through Windows Update.
Whatever your situation is that slow ring Windows 10 Build 14366 has now reached that downloadable ISO stage over this past weekend as Microsoft has now made it available through the Windows Insider website.
Once you sign into the Insider website just go to the PC section and you will be on the download page for the ISO image with an option to either use the Media Creation Tool to put that ISO image on a bootable USB flash drive, DVD disc or just do a direct upgrade using a download of the ISO image.
There are several ISO options available depending on your requirements and testing and they are shown in the below image:
As you can see the previous slow ring build is still available for download if you need that as well.
What current build of Windows 10 are you running as we get closer to the release of the Windows 10 Anniversary Update next month?