Windows 10 introduced the concept of “branches” – a new way of keeping the Operating System updated as part of Windows as a Service. The Current Branch for Business (CBB) is aimed at the majority of business users – giving the opportunity for updates to have been tested before arriving on corporate PCs.
Only the 2 most recent CBBs are supported by Microsoft, meaning that organisations need to be somewhat pro-active in keeping up to date. On November 29th, 2016 Microsoft announced that Windows 10 1607 (aka Anniversary Update) was the new Current Branch for Business and updated media is being provided to Windows Server Update Services (WSUS), MSDN and Volume Licensing Service Center (VLSC).
When the new media hits the VLSC, the grace period for the initial CBB – 1507 – will begin. This means that after May 2017, Windows 10 1507 will no longer be serviced so organisations will need to move up to 1511 or 1607.
The MS post is here