What's New in UEFN 41.20
UEFN 41.20's Verse API surface, from a true file-to-file comparison of the v41.10 and v41.20 digests: 128 new members, 3 changed, 77 removed — and the headline is a full overhaul of the NPC AI-conversation API, with the persona system renamed from llm_* to ai_* and the voice roster replaced by Fortnite character voices.
What's New in UEFN 41.20 for Verse Creators
UEFN 41.20 changes the Verse API surface more than it first appears: a true file-to-file
comparison of the v41.10 and v41.20 digests (fortnite, unrealengine, and verse
digest files) shows 128 new members, 3 changed, and 77 removed. Most of that churn
concentrates in one place — the NPC AI-conversation system — plus one namespace move
that looks like a removal but isn't.
The headline: the AI conversation (persona) API is overhauled
The /UnrealEngine.com/Conversations module — the surface behind AI-driven NPC
dialogue — was renamed and reshaped end to end:
| 41.10 (removed) | 41.20 (new) |
|---|---|
llm_session (Prompt, ClearHistory) |
ai_session (Prompt, ClearHistory, RegisterAction) |
llm_prompt_error / _moderated_ / _throttled_ / _timeout_ / _character_limit_error |
ai_error / ai_moderated_error / ai_throttled_error / ai_timeout_error / ai_character_limit_error |
llm_description_attribute |
ai_description_attribute |
persona_component.RequestToTalk / .SubscribeToResponseType |
persona_component.PromptToTalk / .PromptInterrupt / .GetAISession / .Channel / .Instructions |
basic_prompt / persona_prompt / prompt |
prompt_binding_definition (Name, Description) |
Migration: any island calling llm_session or the llm_* error types no longer
compiles on 41.20 — rename to the ai_* equivalents and move RequestToTalk flows to
PromptToTalk. The new ai_session.RegisterAction is the interesting addition: it
binds a named action the AI persona can invoke, which is the hook for making
conversation actually DO things in your island.
The voice roster: generic voices out, Fortnite characters in
All of the generic named voices (alaina_voice, arthur_voice, luna_voice, and the
rest — 26 removed) are replaced by roughly 40 Fortnite character voices:
peely_voice, jonesy_voice, fishstick_voice, midas_voice,
cuddle_team_leader_voice, brite_bomber_voice, mecha_team_leader_voice,
the_imagined_voice, and more. If your island referenced a removed generic voice,
pick a character voice at migration time — there is no 1:1 mapping.
Not a removal: debug_draw and log moved namespaces
Every UnrealEngine.com/Temporary/Diagnostics member shows as "removed" — but the same
debug_draw, debug_draw_channel, log, log_channel, and log_level surfaces
reappear directly under /UnrealEngine.com/Temporary. This is a namespace move, not
a feature loss: update the using path and existing code compiles unchanged.
Rocket Racing devices
The Rocket Racing device family grows: boost_pad_rocketracing_device and
emp_volume_hazard_rocketracing_device (both with Enable/Disable/IsEnabled and a
TriggerEvent), and vehicle_spawner_rocketracing_device has a changed surface.
Scene-graph itemization
fort_item_pickup_interactable_component gains CanInteract — the native
scene-graph pickup component can now be queried for interactability, which matters to
anyone building custom pickup flows on the component model.
Device quality-of-life
movement_modulator_device: newDeactivate/DeactivateForAllpowerup_device: newClear/ClearForAll
New item and weapon classes
41.20 adds entity classes for the season's loot: the BankShotPistol and
SurgicalBurstRifle families (CH7S3, all rarities), ReconBow (Exotic),
ShockRock/SmokeCloud/FriendZoneBubble items, and an OG Chapter-1 set
(BurstAssaultRifle_OG_CH1S1, PumpShotgun_OG_CH1S*, Grenade_OG_CH1S1,
CeilingZapper_OG_CH1S1, WallDynamo_OG_CH1S1).
Methodology
This article is generated from a direct comparison of the archived v41.10 digest files against v41.20 (all three digests), not from incremental catalog deltas. Digest versions are retained per Fortnite release so every future update article diffs the real files. Epic's release notes and community coverage are the companion sources for gameplay-side changes this API view doesn't capture.
Turn this into a guided course
Add Release Notes — UEFN 41.20 to your free study plan — we'll suggest related pages and stitch the lot into one compile-checked, self-guided lesson with worked examples and quizzes.
Original guide generated by Verse Island from the Verse/UEFN knowledge base, with references to the Epic Games sources above. Code is validated against the knowledge base.