Mythic has posted the patch notes fro the 1.2.1 patch, which added the Keep Upgrade system, combat and RvR improvements, and much more to Warhammer Online.

Own a Keep? Want to keep it? Want to get more out of it? Then the new Keep Upgrade system is perfect for you! Guilds that own a Keep can now purchase upgrades to bolster their hold's utility and defenses in a variety of ways.

Once a Keep has been claimed, a guild member with sufficient permission can speak to the Guild Keep Agent on the upper level of the Keep to choose what upgrades to purchase. These upgrades require a periodic maintenance fee and some are available in multiple levels. Once purchased, upgrades will take time to be completed. This process can be monitored via the new Keep Upgrade Interface. Upgrades will decay if funds are unavailable to pay their maintenance or if a guild member chooses to stop paying for the upgrade.

Read more here.