Microsoft is today promoting Windows 10 build 15063 to the Slow ring for Windows Insiders on both PC, meaning Microsoft is happy with how the build is progressing when it comes to feedback. The build moving to slow ring means it's one step closer to being deployed in the Release Preview ring, at which point it'll be safe to assume this is the build Microsoft intend to roll out to Insiders.
On Monday, I had heard rumors that build 15063 had been signed off on internally, and with the build arriving in the Slow ring today, that rumor appears to be more fact than fiction. If you're an Insider on the Slow ring on PC, you can now download the latest build.
We're expecting Microsoft to release ISOs for build 15063 over the next few days as the build is now available on the Slow ring. Microsoft has said in the past that all Slow ring builds will eventually get ISOs to go with it, allowing people to clean install the build if they wish.