For new family members: the #BranchProgression hashtag is reserved for two things: Windows Insiders on release preview ring are getting final (or near final) build for the next stable version, and a Windows 10 release is made available to more people. In this case, it is the latter.
Windows 10 Version 1803 is now available to everyone. As noted so many times over the course of last three years, please hold off until you see Feature Update to Windows 10, Version 1803 show up on Windows Update. More info can be found at:
There is a more important advisory coming very soon, and it concerns Narrator in the next feature update.