Fortnite v37.40 Ecosystem Update: What UEFN Creators Need to Know
Fortnite v37.40 marks one of the most ambitious Unreal Editor for Fortnite (UEFN) updates of 2025. With the arrival of General Physics in Beta, experimental Custom Inventory and Items, and a full brand content drop for KPop Demon Hunters, this release significantly expands what creators can publish, monetize, and experiment with inside Fortnite.
Unlike earlier preparatory updates, v37.40 removes key blockers: physics-enabled islands can now be published, brand content ships without a publishing hold, and creators gain early access to systems that redefine inventory, items, and physical interaction. This update signals a clear transition from feature groundwork to real-world deployment.
Below is a structured overview of what’s new, why it matters, and where creators should focus next. For full technical implementation details, Epic recommends reviewing the official v37.40 documentation.
General Physics Enters Beta: Publishing Is Now Live
The headline feature of v37.40 is the Beta release of General Physics, which allows creators to publish physics-enabled islands for the first time.
What Physics Enables
With General Physics enabled, creators can build experiences where players can:
- Push, hit, and move objects
- Topple props and structures
- Interact with environments in emergent, reactive ways
- Experience more realistic momentum and collision behavior
Physics-driven gameplay introduces systems that feel predictably unpredictable, opening design space for puzzle games, destruction-based modes, sandbox experiences, and physics-focused combat.
Creators are encouraged to review the Getting Started with Physics documentation before publishing.
Important Design Implications
Physics fundamentally changes gameplay expectations. Creators should:
- Test extensively across devices
- Avoid overloading islands with unnecessary physics props
- Carefully review known issues and limitations
Several devices behave differently or are temporarily disabled when Physics is enabled, making early experimentation critical.
Experimental Custom Inventory and Items
v37.40 introduces the Experimental Custom Inventory and Items system, one of the most transformative gameplay systems added to UEFN so far.
What This System Allows
Creators can now:
- Modify or replace the default player inventory
- n- Design fully custom items with unique properties
- Build systems centered on inventory interactions
- Create gameplay loops such as crafting, economies, and progression
Custom items are built using Scene Graph components, and creators can extend functionality by authoring their own components in Verse.
Current Limitations
Because the system is experimental, several known issues exist:
- NPCs cannot use custom items
- Some inventory inputs ignore remapped keys
- Item placement inconsistencies
- UI and presentation issues
Creators should treat this system as a sandbox for experimentation rather than production-critical content until it matures.
KPop Demon Hunters Comes to UEFN and Fortnite Creative
A major brand moment arrives in v37.40 with KPop Demon Hunters fully landing in UEFN and Fortnite Creative—with no publishing hold.
What’s Included
Creators can now build with:
- A dedicated KPop Demon Hunters Starter Island
- Hero characters including Rumi, Zoey, and Mira
- HUNTR/X NPCs via a Character Spawner device
- Demon enemies using Demon Spawner and Demon Placer devices
- Themed weapons, shaders, props, and background vistas
This content supports bold, melee-focused gameplay and stylized narrative experiences inspired by the franchise.
Creators should ensure they read and follow the KPop Demon Hunters Brand and Creator Rules before publishing.
New Gameplay Additions and Devices
Hive Lobbers
A new wildlife type, Hive Lobbers, has been added to the Wildlife Spawner:
- Fires ranged projectiles
- Burrows when enemies approach
- Can be tamed via device events
- Includes a new Aggression Level setting
Hive Lobbers do not currently support patrol paths.
Verse API for Hive Stash
Verse support for the Hive Stash device is now live, allowing creators to:
- Track stash state dynamically
- Modify appearance and behavior
- Link Hive Stashes to Guard and NPC Spawner devices
This enables deeper narrative and rescue-based gameplay systems.
New Prefabs and Galleries: Reckless Railways
v37.40 expands environmental options with Reckless Railways assets:
- Grand Station Prefab
- Villa and Houses
- Floor and Stairs Gallery
- Wall, Roof, and Props Galleries
- Foundation and Street Gallery
These prefabs support urban, transit, and narrative-heavy island designs.
New Debug Commands and Developer Tools
To support faster testing, new debug commands have been added:
- Set Health – Adjust health as a percentage of max
- Increase Gold Resources – Instantly grant gold
Additionally, the Epic Developer Assistant for UEFN now supports Scene Graph code generation, expanding its usefulness beyond Verse-only workflows.
Ecosystem, Device, and Physics Fixes
v37.40 delivers extensive fixes across the ecosystem, including:
- Weapon and explosive damage corrections
- Improved chat UI responsiveness
- Device validation and behavior fixes
- Major stability improvements for physics-based devices
Pinball Flippers and Bumpers are now physically based, addressing prior latency and interaction issues.
Known Issues to Be Aware Of
Despite the scope of this update, several known issues remain:
General Physics
- Devices cannot be attached to physics-enabled props
- Certain Prop Mover collision issues
- Limitations with Air Vents, Skydive Volumes, and Pinball devices
Custom Inventory and Items
- Inventory selection issues after Edit Mode
- NPC incompatibility
- Input binding inconsistencies
Scene Graph & Verse
- Entity.RemoveFromParent replication issues
Creators should factor these limitations into production planning and testing.
Final Thoughts
Fortnite v37.40 represents a pivotal shift for UEFN creators. Physics-enabled publishing, experimental inventory systems, and major brand integrations elevate Fortnite from a creative platform to a true game development ecosystem.
While not every feature is production-ready, creators who begin experimenting now—especially with Physics and Custom Inventory—will gain a critical head start as these systems mature.
For implementation specifics, configuration options, and ongoing updates, creators should consult Epic’s official v37.40 documentation : 37.40 Fortnite Ecosystem Updates and Release Notes