Fortnite v39.10 Ecosystem Update: What UEFN Creators Need to Know
Fortnite v39.10 is a creator-focused update that hits three high-impact areas at once: brand content expansion (LEGO® NINJAGO®), mobile-first UX improvements, and a critical Verse API change for in-island transactions ahead of publishing opening in early 2026.
If you’re building LEGO experiences, optimizing for mobile discovery, or preparing to ship monetized islands with V-Bucks purchases, v39.10 includes both new opportunities and one immediate action item that you should handle before your next playtest.
This article summarizes the key changes in v39.10 and what they mean for UEFN creators. For full release notes, implementation steps, and official restrictions, please review Epic’s v39.10 documentation.
Action Required: Verse API Change for In-Island Transactions
The most urgent change in v39.10 is a breaking rename in the Marketplace Verse module.
What Changed
- The Verse API class
producthas been renamed toentitlement.
What You Need to Do
If your project uses the experimental release of in-island transactions, you must:
- Update Verse code that references
product - Replace those references with
entitlement
Epic has also updated:
- The In-Island Transactions feature example
- In-Island Transactions documentation
If you’re unsure how to refactor your implementation, start by opening the updated example and mirroring the new structure.
Publishing Status Reminder
For v39.10:
- The experimental flag is removed for in-island transactions
- Publishing does not go live until v39.20
- Publishing opens on January 9, 2026
That means: you can build and validate now, but you cannot publish transaction-enabled islands to players until the January go-live window.
Ask Epic: Mobile Development in UEFN (December 18, 11AM–12PM ET)
Epic is running an “Ask Epic” forum session focused on mobile development in UEFN.
- Date: December 18, 2025
- Time: 11:00 AM – 12:00 PM ET
- Where: Epic Developer Community (EDC) forums
Expected topics include:
- Designing and optimizing for mobile play
- Getting started with Mobile Preview
- Custom Input & Touch Control
- Smaller screen UI/HUD considerations
Creators can submit questions in advance via the forum post. If mobile performance is a priority for your island (or your retention depends on mobile usability), this is a high-value event to track.
LEGO® NINJAGO® Content Arrives (Starter Island + Themed Assets)
The headline content drop in v39.10 is LEGO® NINJAGO®, including a new starter island template and themed assets designed to jumpstart ninja-style LEGO experiences.
NINJAGO Starter Island Template (Art Template)
Creators can kickstart layout and art direction using the NINJAGO Starter Island template, which includes:
- Prebuilt environment designs
- Brick-built modular structures
- Brick Editor-friendly modules you can expand or disassemble
This template is designed to remove early production friction, letting teams iterate quickly on gameplay layers and progression systems.
New LEGO Styles for NPCs
Four NINJAGO-themed LEGO Styles are available for NPC creation via NPC Spawner:
- Earth Master Cole
- Fire Master Kai
- Lightning Master Jay
- Ice Master Zane
These styles add recognizable character identity and support narrative and mission-driven LEGO islands.
Weapons: Shuriken, Nunchuck, and a LEGO-Fit Kinetic Blade
LEGO NINJAGO introduces:
- NINJAGO Shuriken
- NINJAGO Nunchuck
It also brings the Fortnite Kinetic Blade, redesigned to fit Minifigures—giving LEGO creators a stylish melee option with strong gameplay potential.
Props and Brick Modules
The NINJAGO Props Gallery includes training and dojo-themed assets to support:
- Skill challenges
- Combat drills
- Social hub spaces
- Quest progression environments
UEFN projects can begin with Ninjago Monastery brick modules and expand using Brick Editor.
Brick Editor Updates: 23 New Bricks
To support deeper LEGO building workflows, v39.10 adds 23 new Brick Editor bricks, increasing flexibility for:
- Custom structures
- Decorative set dressing
- Functional gameplay architecture
Epic recommends reviewing Brick Editor documentation for details on the new parts.
Mobile UI Enhancements: Cleaner Interfaces on Small Screens
v39.10 continues the mobile-first push with UI tools aimed at reducing clutter and improving readability.
Cinematic Sequence Device: Hide Unused Mobile Inputs
A new option allows the Cinematic Sequence device to hide unused mobile inputs during active cinematics.
- Default: Off
- Use case: cleaner storytelling moments, better onboarding sequences
Popups: Hide Mobile Inputs During Interaction
Mobile gameplay inputs (jump, crouch, fire) are now hidden when players interact with popups. This reduces accidental input and improves touch UX.
HUD Controller: Vehicle UI Hide/Show + Verse API Expansion
Two new HUD Controller settings allow creators to:
- Hide or show vehicle UI
- Control whether the default vehicle HUD elements appear
In addition, new vehicle HUD fields are exposed to Verse, including:
- Fuel
- Speed
- Boost
- Vehicle health
This enables creators to replace default vehicle UI with custom, island-specific vehicle HUD experiences—especially valuable for racing, open-world, or extraction-style modes.
Debug Commands: Infinite Ammo Controls
Two new Beta Debug Command menu options help creators test weapon balance and combat scenarios:
- Infinite Reserve Ammo (toggle)
- Infinite Magazine Ammo (toggle)
These are practical tools for rapid iteration and QA.
New Content: Twinkle Terrace Prefabs and Galleries
v39.10 adds a new themed environment set:
- Twinkle Terrace Tanuki Twinkle Prefab
- Twinkle Terrace Street Prefab
- Floor and Stairs Gallery
- Wall Gallery
- Roof Gallery
- Prop Gallery
These assets are suited for stylized hubs, social spaces, or narrative districts.
Device Updates and Physics Fixes
v39.10 includes multiple targeted fixes, including:
- Reboot Van device options and messaging fixes
- Exposed Henchfan cosmetics for NPC Character Spawner use
- General Physics improvements:
- Fixed Crash Pad and Bouncer Gallery VFX/SFX retriggering issues
- Improved gliding behavior after elevated teleporters
- Explosive device events now trigger properly
- Contrails in Skydive Volumes always visible
- Emoting on moving props no longer locks animation
It also confirms continued fixes for known high-friction issues:
- Air Vent FX no longer playing constantly
- Teleporter now applying direct velocity correctly
- Teleporter no longer teleporting nonstop
- Pinball Flipper rotation corrected on game start
New Device Design Examples: Visual Effect Powerup
Epic adds new Visual Effect Powerup Device Design Examples, showing how to:
- Validate player behavior with VFX feedback
- Reinforce objectives or milestones
- Add lightweight “sparkle” and clarity moments
These examples are useful for onboarding flows, item pickups, and event-driven UI/VFX communication.
Community Bug Fixes and Creator Workflow Improvements
Community-driven fixes include:
- Scoreboard now displays all players correctly
- Asset names display correctly in memory calculation summary
- Save Point device items save correctly
- Memory calculation now launches when using auto-localization
Additional UEFN workflow fixes include:
- Localization export no longer triggers Verse-only pushes unexpectedly
- Entities now collide with actors during drag-and-drop placement
- Better messaging for Island Conversion failures (directs to Output Log)
Scene Graph and Custom Items updates include:
- StackSize/MaxStackSize privacy changes in item_component (now modified via functions)
- Prefab editor improvements and submenu additions
Verse updates include:
- New wrappers for Chapter Seven: Season One items for Custom Items and Inventories
- Fixed StackSize/MaxStackSize incorrect values for Verse-instantiated items
Unreal Revision Control performance improvements specifically target creator-reported lag caused by overly frequent status checks.
Final Thoughts
Fortnite v39.10 is a strong December creator update: LEGO® NINJAGO® expands the LEGO ecosystem with a high-utility starter template, mobile UI enhancements make touch experiences cleaner and more controllable, and in-island transactions continue their march toward publishing—with one important requirement: update your Verse Marketplace code from product to entitlement.
If you’re building for the January 9, 2026 monetization window, v39.10 is a must-read and a must-test release.
For full technical details, updated examples, and the official rule framework, creators should review Epic’s v39.10 documentation : 39.10 Fortnite Ecosystem Updates and Release Notes
