Some new modding features as of 0.34.2.
Retaking lost continents
This is controlled through gameconfig.xml and should be mostly straightforward. Three variables affect the system.
<retakeLostContinents value="0" comment="If set to 1, lost continents may be retaken by eliminating bases in them" />
<lostContinentBaseTicker value="-1" comment="Ticker (for size) assigned to the auto-spawning alien base on a lost continent. If set to a negative number, it uses the main alien ticker" />
<retakenContinentTicker value="500" comment="If a continent is retaken, relations will restart at this point" />
The retakeLostContinents setting has to be set to 1 to enable the system. When the system is enabled, losing a continent will cause an alien base to spawn immediately on that continent. The size of that base is determined by the overall AI ticker if lostContinentBaseTicker is -1, or else that variable can be used to adjust base size.
The player has to eliminate the auto-spawned base, as well as any other bases that may be present on the continent. Once there are no more alien bases left, the continent returns to the game and its relations value when returned is determined by retakenContinentTicker.
Custom categories in manufacture UI
A new file called manufacture_categories.xml provides the ability to add new categories shown in the workshop screen (like the default ones Aircraft/Soldiers/etc).
Since the hardcoding of categories is removed, it's important that in manufactures.xml the FillsSlot column is only used by vehicles and aircraft.
Add a new manufacturing category like:
<ManufactureCategory>
<ID>SomeCategoryId</ID>
</ManufactureCategory>
Where SomeCategoryId also needs to be a string identifier entered in strings.xml.
Controlled zombification / unit spawning
A bigger change concerns the game's Zombify and SpawnReaper abilities. For Zombify (victim gets turned into a zombie upon death) and SpawnReaper (unit turns into another unit later), you can now specify the race and rank of the unit to spawn. For SpawnReaper, the duration in turns can be specified as well.
Normally, a Reaper has:
Abilities="Zombify"
To use the modding ability, you have to specify a string that looks like Zombify.Race.Rank. For example:
Abilities="Zombify.Sebillian.Guard"
This would turn victims into Sebillian Guards.
Zombies have a SpawnReaper ability, and to use modding for it you have to write SpawnReaper.Race.Rank.N where N is the number of turns after which the transformation takes place. So you could express the vanilla game of spawning a Reaper after 5 turns like:
Abilities="SpawnReaper.Reaper.Reaper.5"
Note: You have to specify a number for SpawnReaper if you're modding it, you cannot just specify race and rank.
You can of course chain units with SpawnReaper abilities to make a progression of different units. The SpawnReaper ability name is then confusing but has to be kept around for legacy purposes.
Aliens with the SpawnReaper ability will turn into another unit after that timer, but also if they are killed. You may want to avoid that in order to create aliens that can be killed by Xenonauts to prevent them from "evolving". That can be done by adding the Permadeath ability to a unit with the SpawnReaper ability. Like this:
<Abilities="SpawnReaper.Reaper.Reaper.5,Permadeath">
That would prevent a spawn in case the unit suffers a violent death (from Xenonauts, local forces or alien friendly fire) before the timer is up.
Melee aliens vs. vehicles
Aliens with melee weapons, such as Reapers, can now also attack vehicles, but only if that AI behaviour is enabled by a MeleeVehicles ability. So to make vanilla Reapers attack vehicles, you would add the ability to them:
Abilities="Zombify,MeleeVehicles"