The Instanced Dungeon system has been added. This system allows multiple parties to simultaneously enter different instances of an area for a certain period of time.
Dark Cloud Mansion pictured below

Entry
Each dungeon can be entered via an Entrance NPC. Certain requirements must be met in order to enter an instanced dungeon, including a set level, number of party members, a specific item, and/or a quest. Some conditions and requirements are listed on the next tab.

The request to enter an instanced dungeon must be made by the party leader.

There is a limit to the number of instanced dungeons players may enter per day.

If players are moved outside of an instanced zone by teleporting to the nearest town after death, or by using a Scroll of Escape, they can re-enter the area as long as their instance of the dungeon still exists.

If players log in after logging out inside an instanced dungeon, they are moved outside the dungeon. After rejoining the party, they can re-enter the area as long as their instance of the dungeon still exists.

If a party leader has already initiated the instance, they cannot invite a new member to join there party from inside the instance. The party’s size cannot be increased once they are inside the dungeon.

Players cannot use the Party Member Summon Skill while inside instanced dungeons; however, the Party Member Summon Skill can be used to summon original members of the party upon entry that are inside the castle/fortress-related dungeons.

Exit
Players are automatically moved outside an instanced dungeon in following situations:

Mission Completion: Players within an instanced dungeon are moved outside after five minutes of completing a mission. (This only applies to zones that do not have a teleport cube in them.)

Time Limit Reached: If the allotted instance time runs out, the party will be moved outside of the instanced dungeon.

Server Issues: If any server-related technical problems occur, such as a server outage, all instanced dungeons will be reset and players are moved outside of instanced dungeons.

Instanced Dugeon Reset
The instanced dungeon resets if all the party members who were inside leave the area. Below are the specifics on when each instanced dungeon resets after all party members leave:

The following dungeons reset immediately: Nornil’s Garden and Dark Cloud Mansion.

The following dungeons reset after 20 minutes: Castle/Fortress Instanced Dungeons and Crystal Caverns.

If a mission is completed, or the time limit is approaching, the remaining time is displayed.

Time Limits and Refresh Times
Each dugneon can only be occupied for a specific period of time. And once used, the instanced dungeon can be re-used only after a certain period of time has passed. The instanced dungeon time limit and refresh times are as follows:

Dungeon Time Limit Refresh Time
Nornil’s Garden 70 minutes 2 hours
Dark Cloud Mansion 30 minutes no limit applies
Crystal Caverns 90 minutes 24 hours
Underground Dungeon (Castle) 60 minutes 4 hours
Fortress Dungeon 60 minutes 4 hours

New Command
/instancezone is a newly added command. This command will show the time remaining before you can enter the instanced dungeons again.