The keep doors and walls (main keep only) can be upgraded, as well as a LifeNet Generator that will enable keep respawning capabilities. The Death Toll Keep Upgrades Merchant mentioned above sells items that are to be used on whatever you want to upgrade.
There are now NPCs that stand next to each upgradeable object and will provide the current upgrade status if spoken to.
Keep Barrier Tier Upgrade items, when used on the door or wall of the keep, will increase the progress towards the next Tier Level of the door. This will significantly increase the door’s health. Keep Barrier Reinforcement items will “reinforce” the door, giving it more defenses and effectively lowering the amount of damage it takes from attacks. Each time the tier level of the barrier changes, it will lose any reinforcement status it may have had. Additionally, as the Tier Level of the door increases the door model will change. Each of the 4 Tier Levels has a different appearance. There is a known bug that causes the model change not to show up for anyone near the door at the time of the upgrade. If you log out and come back in or just run far enough away and back, you’ll see the correct model. The wall only has two models. It will appear one way for Tiers 1-3 and then another way for Tier 4 (max).
The LifeNet Generator will start out as a “Broken LifeNet Generator”. While in this “broken” state, players are not able to respawn at the keep and the LifeNet Generator should not be able to take damage. The Broken LifeNet Generator cannot be upgraded for 5 minutes after it spawns in. This is typically only a factor when enemy players destroy the LifeNet Generator and then it should very quickly respawn as a Broken LifeNet Generator. The LifeNet Generator should never be missing from the keep for more than about 10 or 15 seconds.
When the LifeNet Generator is upgraded from “Broken” status to Tier 1, the model will change to a repaired version and players will respawn inside the keep with 25% health when they die. They also should not lose any consumable buffs like they would if they respawned in a normal LifeNet facility. Upgrading the LifeNet Generator to Tier 2 will allow players to respawn at 50% health. Tier 3 is 75% health, and Tier 4 respawns at 100% health and also grants a small buff. Gamma and Stamina levels are affected similarly, but they are never lowered below the value they’re at when you die.
The LifeNet Generators are visible from outside the keep and can actually be damaged by players from outside the keep if their weapon has enough range.