Blizzard Entertainment announced the data pertaining new Battle.net system and other changes is now downloadable in preparation for the coming expansion Diablo III: Reaper of Souls.
The expansion will go live on March 25th, 2014 -- however, you can skip the download time on launch date by downloading most of the data right now. It is a 6GB file. Simply, launch the Battle.net Launcher. If you are currently testing PTR or beta, then switch back to Diablo III vanilla. It will begin a cycling icon to alert you it's downloading data. To the right of the cycling icon you will notice a pause icon and a gear icon (which gives the option to look at settings or to stop all current downloads).
Visit the Diablo III website to learn more about this pre-expansion download.
[bluepost]Lylirra: As of this week, you may notice that the Diablo III game launcher and Battle.net desktop app will begin downloading data for a "future patch." This download is in preparation for the March 25 launch of Reaper of Souls, as well as a pre-expansion patch that will be released in the coming months.[/bluepost]