"Hi everyone, today we are releasing the ISOs for Windows 10 Insider Preview Build 10130. We are not, however, releasing Build 10130 to the Slow ring due to several bugs we’re looking to fix," Microsoft explained. "Once we have these fixes in hand and ready to push out to Windows Update, we’ll consider pushing Build 10130 to the Slow ring. I know we said we would only release ISOs if we push a build to the Slow ring but we’re making a special exception today. We know that a bunch of Windows Insiders on the Fast ring are currently blocked getting to the latest build due a 0x80146017 error. With the ISOs, they can mount the image and upgrade directly from the ISO and get unblocked."
Fast ring and Slow ring refer to the speed at which you choose to receive updated Preview builds of Windows 10. Those who choose the Fast ring will see updates quicker than those who choose Slow ring, but they'll have to contend with more bugs and other issues that Microsoft hasn't had a chance to stomp out.
For this release, users will see some UI improvements, such as customizable Start menu and updated icons. Microsoft also removed the border around the Action Center for a nicer, more polished look. Other changes include Jump Lists that now match the rest of the UI for the Start and Taskbar in Windows 10, various improvements to Microsoft Edge (Project Spartan), more advanced print options, Taskbar settings for Virtual Desktops, and a few other tweaks.
Windows 10 will release to the public on July 29. Existing Windows 7 and Windows 8.1 users will be able to upgrade to Windows 10 for free for the first year, otherwise the OS will cost $119 for Windows 10 Home and $199 for Windows 10 Pro.