Trench Digging, C-130J Airborne Drops, and the 128-AI Cap: New features and mods in Arma Reforger 1.9 and COMRAD #29

Driven by Update 1.9 and breakthrough community mods, Arma Reforger has become a top platform for large-scale milsim units by adding synchronized terrain deformation, C-130J airlifts, and massive 61×61 km maps. Because the update also brings built-in magazine repacking and hydration, realistic vehicle physics, and a strict 128-AI global cap, unit staff and mission makers must prune redundant mods and use dynamic AI spawning for future operations.

If you looked at Saturday's Top 10 Milsim Units This Week: Debut Rankings (Oct 23–29, 2026) on the MilSim Units Blog, one number probably jumped right off the page: six out of the ten most voted units on the entire platform are now running Arma Reforger.

A year ago, plenty of veteran Arma 3 leaders (myself included) still had a list of things we felt Reforger needed before a multi-platoon realism unit could fully commit. We wanted better vehicle physics, cleaner AI management for Game Masters, heavy airlift options for airborne units, and battlefield fortifications that actually felt alive.

Over the past few weeks, between Bohemia Interactive's Changes and Improvements in 1.9 Modding Update and Friday's Community Radar #29 (COMRAD #29) on October 30, a huge chunk of that wishlist is either sitting on the Experimental branch right now or live in the Workshop. Here is a full breakdown of what is changing and what your unit's command staff, S-2 mission makers, and modpack managers need to prepare for.

BUT FIRST: Whether your unit is already running 60-player Reforger campaigns or you're looking for a tactical community to call home this November, browse over 660 active Reforger groups on MilSim Units, and if you're hosting heavy modded scenarios, compare vetted hosts on the MilSim Units Server Providers Directory.

1. Multiplayer Terrain Deformation: Digging Real Trenches and Fighting in Mortar Craters

For years, one of the biggest limits in military simulation games was static ground. You could drop twenty 82mm mortar shells or 500-pound bombs on an open field, and when the smoke cleared, the grass was still completely flat with zero cover for the infantry pushing across it.

In Community Radar #29, Bohemia spotlighted a breakthrough experimental system by modder steffenbk1 (tested in the Mud Arlanda scenario) that brings synchronized multiplayer terrain deformation to Reforger:

Entrenching in the Field: Soldiers can dig actual physical trenches into the dirt, creating real below-ground fighting positions instead of just stacking tall sandbag walls on top of flat grass.
Mortar Craters as Dynamic Cover: Artillery and mortar barrages physically gouge craters into the terrain that replicate across the server for every player, giving advancing fireteams real shell holes to bound into when crossing open ground.
Deepening Convoy Wheel Ruts: Heavy logistics trucks and armored vehicles leave deepening ruts in mud and dirt roads over the course of an operation. For Recon teams and combat engineers, spotting heavily rutted dirt tracks gives you a real visual clue of which supply route the enemy is using, and where to plant mines or set up an ambush.

2. True Airborne Operations and Massive 61x61 km Terrains

If you run an Airborne infantry platoon or a dedicated aviation detachment, two community releases featured in COMRAD #29 open up entire campaign styles that used to be restricted to Arma 3:

PandaMods' C-130J Super Hercules: This isn't just a reskinned cargo plane model. It comes with a custom flight model, working cockpit MFDs, autopilot, and a fully walkable cargo bay. Aviation crews and S-4 logistics teams have to physically load vehicles and supply crates into the fuselage, and airborne platoons can stand up, hook up, and walk out the ramp on the green light for static-line or HALO insertions.
ToH Seattle Extended (61x61 km): Ported by Jove Chiere, this work-in-progress terrain spans a massive 61 by 61 kilometers of dense city blocks, industrial harbors, and rural countryside. One complaint pilots often have on smaller islands is that helicopter flights take two minutes from takeoff to landing zone (LZ). A 61x61 km map gives rotary and fixed-wing pilots real flight times, forces units to establish Forward Arming and Refueling Points (FARPs), and lets S-2 teams run multi-week campaigns across a single map without fighting over the same three towns.

3. Server-Authoritative Magazine Repacking and Usable Canteens in 1.9

Every unit tech team knows the pain of patch day: a new game update drops on Thursday, three small quality-of-life mods break, and suddenly nobody can load into the server for Saturday training.

According to Bohemia's Changes and Improvements in 1.9 guide, Update 1.9 moves magazine repacking directly into vanilla as a server-authoritative system (defaulting to CAN_WHEN_OTHER_CONTAINS_THIS_AMMO_TYPES so soldiers can combine partially spent magazines of matching ammo types, or even mix ball and tracer rounds when configured). On top of that, 1.9 adds hydration and usable canteens right into the base platform.

If your unit currently runs standalone mods for mag repacking or hydration, have your tech staff check your modlist before 1.9 hits stable, removing redundant scripts now will save you from mod conflicts on operation night.

4. Overhauled Wheeled Vehicle Physics (And Why Your Convoy Drivers Need Practice)

Anyone who has driven a supply truck in Arma knows how weird vehicle physics can get at high speeds. In Update 1.9 and Dev Report #24, Bohemia completely reworked wheeled vehicle simulation using an updated tire friction model, mechanical trail, scrub radius, and steering-wheel force feedback.

In practical terms for units: trucks and armored wheeled vehicles carry their weight much more realistically on corners, wet roads, and off-road slopes. If your unit has dedicated drivers or a motor pool qualification course, it's worth hopping onto the Experimental branch now so your drivers get used to the new braking distances before they accidentally roll a troop transport full of two squads into a ditch.

5. The New 128-AI Cap and 800-Meter Eviction Rule for Game Masters

This is the single most important technical note in the 1.9 Modding Update for every Zeus and S-2 mission maker:

One Hard AI Limit (Default 128): Update 1.9 simplifies AI budgets so there is now only one global AI limit that matters, set to 128 by default. When that limit is full, new spawn points are skipped before the group entity is even created.
800-Meter Safe Zone: Low-priority AI groups can no longer evict other groups, and any AI group within 800 meters of a player is completely protected from eviction.
Driver Persistence: If even one member of an AI group has a permanent simulation LOD, such as a vehicle driver, that single AI keeps the entire group active.

For mission makers, this means you shouldn't pre-spawn 120 idle AI across the rear of the map at the start of the night, or your forward ambush triggers won't spawn when the platoon reaches the objective. Use dynamic triggers or spawn waves phase-by-phase as the platoon advances, and your server FPS will stay rock-solid all night.

How Is Your Unit Preparing for 1.9?

Which of these features, trench deformation, the C-130J airlift mod, or the 1.9 vehicle and AI changes, will make the biggest difference for your Sunday operations? Let us know in the comments, and make sure your community is listed and voting on MilSim Units!