Revit 2015 Update Release 8 is now available from the following page:
This update utilizes a new installer which presents the user with a simplified path to install UR8. This update applies to the following products:
Building Design Suite 2015, Infrastructure Design Suite 2015, Plant Design Suite 2015, Revit 2015, Revit 2015, Revit Architecture 2015, Revit MEP 2015, and Revit Structure 2015.
For the above products, the version of Revit should be detected and the appropriate update will be installed.
Revit 2016 Service Pack 1 is also available from the following page:
This update also utilizes the same updated installer and applies to the following products:
Revit 2016, Revit Architecture 2016, Revit LT 2016, Revit MEP 2016, and Revit Structure 2016.
Enhancement documentation is available on each download page as well.