Windows 10: Obtaining November 2015 (1511) Update
The November 2015 update for Windows 10 (Version 1511) is a substantial update akin to the major updates issued as Service Packs for Windows NT to Windows 7.
For new systems, the update package will be delivered via Windows Update in the usual way. But systems that have been upgraded to Windows 10 from Windows 7/8 will not be offered the update until 31 days after the upgrade. This is because Build 1511 is essentially deployed like a new operating system and needs to be rolled back, if necessary, by reverting to the previous operating system as opposed to simply uninstalling an update, which is the behaviour for Windows Vista to Windows 8.1. The 31 day window is to provide an opportunity for the system to be rolled back to Windows 7/8 before negating that ability when 1511 is installed.
However, to allow Windows Update to install Build 1511 immediately, simply run Disk Cleanup and remove the Windows 7/8 files rollback/uninstall files. Then check for updates in Windows Update and the update should appear.