This new system will allow each character to defeat each raid encounter once a week.

Blizzard announced about six months ago that their philosophy on raiding in Cataclysm will be focused on flexibility. You should be able to choose whichever size raid fits your style, and you shouldn't have to run the same content twice in a week to maximize your character. With that in mind, Bashiok just posted an in-depth look at the Flexible Raid Lock System that's coming in patch 4.0.1.

The new system will debut in Icecrown Citadel and The Ruby Sanctum when the patch launches, but it will ultimately be featured in all Cataclysm and Wrath of the Lich King raids once the expansion is live. The Flexible Raid Lock System will allow each character to defeat each raid encounter once a week. Here's Bashiok's example: "You could kill Lord Marrowgar and Lady Deathwhisper with a 10-player raid on Wednesday, join a 25-player raid to kill Festergut and Rotface on Thursday, and then lead a completely new 10-player raid to kill The Lich King on Friday."

To help plan out your raiding schedule, a new UI element will be introduced that shows you which bosses you have already defeated. Raid leaders will also have the ability to link in chat which encounters the raid has completed. Bashiok goes into much more detail on the system in his post, so be sure to read it after the jump.

Flexible Raid Lock System in 4.0.1

Almost six months ago we announced that Cataclysm raids were being redesigned to make both raid sizes the same difficulty, drop the same quality of loot, and exist in the same lockout. This evolution in raid philosophy is built on the belief that the size of your raiding group should be a choice based solely on what's more fun and enjoyable for you, and that you should not have to complete the same raiding content twice in a week to maximize your character's progression. These systems are the culmination of a great deal of design and player feedback from the last few years. With the release of the 4.0.1 patch, the new Flexible Raid Lock system will debut in Icecrown Citadel and The Ruby Sanctum.

With the Flexible Raid Lock system, instead of being locked to a specific raid size or raid group, each character will have the opportunity to defeat each raid encounter once a week. You could kill Lord Marrowgar and Lady Deathwhisper with a 10-player raid on Wednesday, join a 25-player raid to kill Festergut and Rotface on Thursday, and then lead a completely new 10-player raid to kill The Lich King on Friday. Every raid has a list of encounters associated with the zone. For example, Icecrown Citadel has twelve encounters. After you defeat Lord Marrowgar, you can open up your character's raid information dialog and see the list of encounters in Icecrown Citadel with Marrowgar marked as defeated. You may no longer fight Lord Marrowgar with any raid size or difficulty until the weekly raid reset for your region occurs.

Another key change is that if you join someone else's raid in progress, you are no longer locked to that raid after merely zoning in. Your raid status will only change when a boss is defeated, at which point it will be updated to reflect the state of the instance in which you are currently participating. So, let's say you have killed the first four bosses of Icecrown Citadel, and you then join a raid that has defeated the first four encounters, as well as Festergut and Rotface. The dialog that displays upon entering Icecrown Citadel will show that the raid has defeated 6 of 12 encounters. If you help them defeat Professor Putricide, then you would be marked as having defeated not only Professor Putricide for the week, but also Festergut and Rotface. If instead after joining the raid you then proceeded to wipe ten times to Professor Putricide, you could leave the raid with only the first four bosses marked as completed.

To help communicate to players which bosses are dead in the raid leader's raid, there is new functionality to link in chat a list of the encounters the raid has defeated. So before you join a raid, you can see what they've already defeated. If a raid leader advertises in chat that she needs another healer for an 8/12 Icecrown Citadel run, you can see precisely which bosses are still available to fight. If you were only looking for that one item from Queen Lana'thel that never drops for you and this raid already defeated her, you will know not to join that raid.

Let's look at another example of the Flexible Raid Lock system. A guild schedules three nights for 25-player Icecrown Citadel raiding on Wednesday, Thursday, and Saturday. On Wednesday, the raid defeats Lord Marrowgar, Lady Deathwhisper, Icecrown Gunship Battle, and Saurfang. On Thursday, five people cancel their raid attendance due to real life emergencies. The raid leader knows that if he cancels Thursday raiding, there's little chance they'll have enough time on Saturday to defeat the other eight bosses in Icecrown Citadel. So he splits the remaining 20 Thursday raiders into two 10-player raids. Each new raid enters Icecrown Citadel and defeats Rotface, Festergut, Blood Council, and Valithria Dreamwalker. The next Saturday with all 25 players online, they reform as a 25-player raid and enter Icecrown Citadel once more. Only Professor Putricide, Queen Lana'thel, Sindragosa, and The Lich King remain. After a tough fight, the Lich King falls and everybody celebrates. Without the Flexible Raid Lock system the entire raid probably would have missed out on a night of raiding, and likely would not have reached the Lich King.

While players can freely move between raids of different sizes in normal difficulty, there are some additional rules for Heroic difficulty. If a 10- or 25-player raid defeats a boss on Heroic difficulty, then those players may now only raid additional Heroic encounters with that specific raid. If your Heroic 25-player raid defeats the first four bosses of Icecrown Citadel on Heroic, then they may not split up into two 10-player raids and continue to fight in Heroic difficulty. You may also not join someone else's raid if they have defeated a Heroic encounter.

But let's say you are a member of a Heroic raid in Icecrown Citadel, and after killing Lord Marrowgar on Heroic you have Internet connection issues that prevent you from raiding for two nights. During those two nights, the rest of the raid kills everything. Without the Flexible Raid Lock system, you would be done with raiding Icecrown Citadel for the week. Ouch. With the Flexible Raid Lock system, you can join someone else's raid as long as they are doing Normal difficulty. This would at least give you the opportunity to earn your Justice Points for the week. If this raid attempted to switch to Heroic difficulty for Icecrown Gunship Battle with you in the raid, the raid leader would receive an error message stating that she cannot change to Heroic, because someone in the raid (i.e., you) is already locked to a different Heroic instance.

All of the new Cataclysm raids will feature the Flexible Raid Lock and Dynamic Difficulty systems, and when the Cataclysm occurs the other Wrath of the Lich King raids will also have these features. It's important to note that this system doesn't affect Heroic dungeons, they will work as they always have. We look forward to feedback for this new system after 4.0.1 is released. As a reminder, Icecrown Citadel and The Ruby Sanctum are the only two raids that support the Flexible Raid Lock until the Cataclysm occurs.