October 10th saw the end of security and quality update's for Build 1511. So if your currently using this build and would like to carry on receiving updates you'll need to update to a later version which you can do by either running Windows Update or using the Link Removed.
Ref...
education edition
end of service
enterprise edition
home edition
it professionals
lifecycle
microsoft
november 2015
pro edition
qualityupdates
security updates
support
troubleshooter
update guide
update issues
version 1511
version check
vulnerabilities
windows 10
windows update
