It's only been a few days since Microsoft released Windows 10 Insider Preview build 17127 to the Fast ring, but it's already been promoted to the Slow ring. The news comes alongside the release of build 17128 to the Fast ring.
Obviously, there's not been a lot that's new since Windows 10 build 17120, which is the build that 17127 replaces in the Slow ring. Windows 10 Redstone 4 is almost done, and is Microsoft doesn't sign off on an RTM build today, it will do so early next week.
Here's what's changed since the last Slow ring build:
Dona Sarkar and Brandon LeBlanc, who co-authored the blog post, said that Microsoft will be releasing ISO images for the build next week. The most recent ones available were build 17115.
There are no known issues in Windows 10 Insider Preview build 17127, which also means that the Windows Mixed Reality issues have been fixed. As usual, you can install it by going to Settings -> Update & security -> Windows Update -> Check for updates.