The 2015 Watchtower Library on DVD for Windows has an update available. If you clicked on the box to update and you are connected to the internet, it will bring up a box and ask you if you want the current update (212 MB). It adds the 2016 Wt and Awakes , some brochures, the Meeting Workbooks and other things.
As of the 2015 DVD release, the plan is to release updates twice a year: in July and in January.
As of the 2015 DVD release, the plan is to release updates twice a year: in July and in January.