Windows 10 1809 aka RS5 as well as Windows Server 2019 have both been released today 11/13/2018 as of 10AM PST. I do not see the new ISO files available on Visual Studio/MSDN as of yet.
Full article below.
“On November 13, 2018, we will begin the re-release of the Windows 10 October Update (version 1809), Windows Server 2019, and Windows Server, version 1809. We encourage you to wait until the feature update is offered to your device automatically.
Note for Commercial Customers: November 13 marks the revised start of the servicing timeline for the Semi-Annual Channel (“Targeted”) release for Windows 10, version 1809, Windows Server 2019, and Windows Server, version 1809. Beginning with this release, all future feature updates of Windows 10 Enterprise and Education editions that release around September will have a 30-month servicing timeline. “