Happy Update Day UEFN Community! Epic shipped 55+ changes in v42.10. One of them lets your island know which players walked in together.
▶ WHAT'S NEW IN UEFN v42.10
The Social Synergy API is live in Verse. Call GetLocalParty() on a player and you get back the party members who are in the session with them, plus events for members joining or leaving. Party score bonuses, party-only doors, difficulty that scales with group size. Your island can finally treat "came with friends" as a first-class game state.
55+ CHANGES LOGGED | 4 NEW EXPERIMENTAL | 1 BREAKING CHANGE |
CASE FILE
UEFN · SOCIAL
Every retention deck you have ever seen says the same thing: players who play with friends stay longer. Until today, a UEFN island could not tell the difference between four strangers and four friends who queued together. Now it can, with a few lines of Verse. Groups are now a design input, not a matchmaking accident.
PATCH NOTES
Released September 3, 2026. Every item below is from Epic's official notes; links go straight to the docs.
THE TL;DR
NEW Social Synergy API, GetLocalParty() reads party membership, size, and join/leave events in Verse. Not marked Experimental.
NEW Verse Camera Transitions (Experimental), Blend and Cut transitions now work for cameras built with the Experimental Camera API. Still cannot publish.
NEW Harrowville: Environment template, plus a full Harrowville prefab set and 166 new horror audio assets. Halloween season starts now.
NEW Like, Save, Follow in-game, players can like your island and follow you from the Overview tab mid-session, not just on exit.
NEW Mobile Preview device selection, pick popular iOS and Android devices; the preview adds corners, camera cutouts, and correct safe zones.
NERF concrete_subtype validation tightened, @editable fields of type concrete_subtype holding non-<concrete> types now fail validation. Fix before you republish.
Breaking changes, do these first
@editable concrete_subtype fields must hold <concrete> types. Epic fixed the editor-side validator so it now actually enforces the rule that anything in concrete_subtype(foo) is also <concrete>. Already-published islands keep running, but you will hit validation errors the next time you republish. Change the type or remove the field. Release notes
Lightsaber prefabs copied from the Lightsabers and Force Powers template had the wrong item category and were unusable. Epic fixed the template, but projects that copied the prefabs must reset that field manually.
GetLocalParty() returns a group object of the party members present in the current session. Import the Social, AgentGroup, and Simulation modules (exact paths are in the docs). Docs
GetMemberMap() gives you the members (and .Length gives you party size). AddMemberEvent and RemoveMemberEvent fire on join and leave.
Two players in the same party get the same group reference, so = tells you if they are together.
A solo player is always a party of one. The group only contains members who are actually in your session; the party itself can extend beyond the island.
Epic's own list of what to build: score bonuses and achievements for parties, party-only door access, difficulty that scales to party size, reduced friendly fire between party members, team rebalancing to group or split parties, dynamic commentary and UI.
Context: parties now form across the Epic ecosystem (Fortnite, the Epic Games Launcher, and the Epic mobile apps). Epic Party blog
Why this matters more than it sounds: a party is a real social graph edge, not a team color. You can now reward it, gate on it, and design around it, and the friend who was dragged along is exactly the player you want to convert into a follower.
Cameras (Experimental)
Blend transitions for a smooth change between cameras, Cut for an immediate switch, both parametrizable at runtime. Docs
The camera_director_component picks the highest-priority registered camera each frame and handles the blend when the active camera changes. Directors can nest inside directors.
EaseOut re-exposed as Experimental in Scene Graph.
Caveat worth repeating from 42.00: the Camera API, Camera Modifiers, and transitions are all Experimental, and Epic still says you cannot publish a project that uses Scene Graph camera components. Prototype your top-down or cinematic idea now; ship it later.
Discovery: Liking, Following, and Saving
Epic says this is "the first of several updates arriving over the next few releases."
Like, Dislike, Save, and Follow are now on the in-game Overview tab (inventory, map, or score key binding). Players can follow you while they are still playing.
In the exit flow, like and dislike are one linked control; players switch directly instead of clearing their choice first.
Selected states now read in past tense (Liked, Saved) and the bright selected background is gone.
Following shows a check instead of a plus, and the label reads Following.
For brands: the follow button is now reachable at the moment of peak fun, not the moment of leaving. Put a "follow us" beat in your loop.
Mobile
Mobile Preview device selection, choose from popular iOS and Android devices; the preview renders corners, camera cutouts, and correct safe zones for that device. Docs
Mobile Preview still runs only inside a Live Edit session and uses cooked PC data, so treat performance and memory numbers as approximate.
UE Remote app, replicate touch inputs from a real iOS or Android device onto your development workstation to test native gesture recognition. Pairs with Virtual Pointer, which graduated in 42.00.
Verse, input & tools
Move input action added to the TraversalMapping context (Experimental). Subscribe to it to react to movement keybinds.
InteractMapping and Interact action added (Experimental). Subscribe to react to the interact keybind.
Programmatic toolset for Unreal MCP, MCP clients can now batch multiple tool calls into a single script. Follow-up to the MCP server that landed in 42.00.
Non-private assets now always place a redirector when moved or renamed, and so do assets used by Verse-compiled code. Fewer broken references after a cleanup.
Fixed @editable concrete_subtype fields not being validated properly (this is the fix that causes the breaking change above).
UEFN editor
Fixed the phone tool not working with the Custom Items and Inventory project setting enabled.
Fixed a load-time regression that could stop maps with a large number of scene graph entities from loading on some platforms.
Fixed a player reference being held after the player left, logged off, or was eliminated, which caused garbage collection hitches.
Physics
Sliding felt sluggish and jittery on physics-enabled islands; it now feels consistent regardless of island settings.
Telekineticon now grabs only the prop the player is aiming at, not nearby props.
Custom icons assigned to the Telekineticon entity now show up in-game.
Players no longer spawn in the air at game start or between rounds on physics islands.
Equipped weapon no longer disappears while sliding after a sprint on physics islands.
Scene Graph
Fixed looping skeletal animations that played on the server but appeared frozen at their end pose on clients.
EaseOut re-exposed as Experimental.
Community-reported fixes
Credit where it is due; these came from creators filing on the forums.
VFX Powerup Device glow and outline effects now appear on players. Report
Jetpack hover-in-place is back; ADS in the air after activating to hold height. Report
SetPresentableToPlayers is now consistent across entities sharing the same component. Report
Stat devices now target custom stats. Report
Custom items and currency now appear in the inventory UI. Report
The Dev Assistant no longer silently times out while looking like it is loading. Report
Lightsabers had the wrong icon. Report
Ecosystem & weapons
Weapon tag fixes: Unstable Thunderclap DMR (removed Assault, added Marksman), Overdrive Pulse Rifle (added Exotic), The Foundation's Rift Rifle (added Marksman). If your loot pools filter by tag, re-check them.
First-person mesh visibility now catches meshes that do not fully exist at initialization, so certain meshes are no longer unintentionally visible in first person.
CP_Prop_Rock_Wall_Moss now allows color selection for the top moss.
New foliage Brimstone_DeadGrass_A and Brimstone_DeadShrub_A under Fortnite > Environment > Foliage; new paintable landscape material MI_Hera_Grass_Covers_Boreal_A under Fortnite > Environment > Materials.
Brand islands
Force Mind Trick now removes borrowed outfits in every case.
Lightsaber prefabs fixed (see breaking changes for the manual reset).
New content
Template: Harrowville: Environment, horror assets plus lighting and environment techniques for a "freshly horrifying" atmosphere.
Harrowville Set: Floor/Stair/Roof Gallery, Wall Gallery, Prop Gallery, Cliff Gallery, Harrowville House.
Cluster Coast Set: Floor, Wall, Roof, and Prop Galleries, plus the Duck Yacht and Salty Duck prefabs.
Audio: 166 new Audio Control Buses, Music, SFX, and Vocals under Fortnite > Audio > Horror.
Weapons: Striker Burst AR in Rare, Epic, and Legendary for Creative and UEFN.
Docs: Prop Mover limitations are now written down. Only one Prop Mover can be active at a time, the last one activated wins, and the active mover can rotate or translate but not both. Docs
What is NOT in this release
No new Verse camera modifiers, no Ability System changes, no new devices.
No Landscape, Materials, Performance, Lore, or Asset Health sections this time (42.00 had all of them).
No monetization, payout, or island metrics changes. The discovery movement is the Like/Follow/Save UI, and Epic says more is coming.
No dedicated Known Issues section.
★ READ THE SOURCE ★
THE FULL 42.10 NOTES: https://dev.epicgames.com/documentation/fortnite/42-10-fortnite-ecosystem-updates-and-release-notes
That's the play. Happy UEFN v42.10 Update Day!
Lee Graham (OFF THE X)
Social Synergy API