The upcoming patch for Diablo 3, patch 1.07, makes a broad number of changes across the board in addition to adding PvP dueling, including tweaks to the Battle.net interface and how characters react to taking damage, according to the patch notes posted on Battle.net.
With the new PvP dueling system, Blizzard intends to create a "safe, opt-in location" where players can challenge each other without suffering the "griefing" players would in Diablo 2. Groups of two to four players can now challenge one another in a new zone specifically designed for this type of dueling. The zone is accessible by speaking with a specific character, Nek the Brawler, at the New Tristram inn.
Blizzard has increased the base item pick-up radius to 3 yards from the original 1.5 yards, and players' who are killed multiple times in a row will no longer have more time added their resurrection timer. The patch also corrects a "flinching animation" error that caused players to temporarily lose control of their characters after being hit by multiple enemies in the same moment.
Players will now be placed in a town when resuming a game. Players who wish to return to their last known checkpoint will have access to a portal that will take them there.
Battle.net has also gone through a few tweaks. The site UI now displays how many players are online and the "Report Botting" option has been added to the right-click player menu.
The full rundown of patch 1.07 can be read on Battle.net.