What changed for creators in UEFN 42.40

Epic shipped 42.40 on October 15, 2026. This page is the set of changes that break or unblock an island: custom abilities you can publish, a field rename that changes units, text chat channels, a VerseVM session toggle, a mobile HUD switch, and one unconfirmed weapon bug the notes do not mention.

More walkthroughs are in the guide library. Release cards are on What's New.

Publish custom abilities

Abilities and Fortnite Template Abilities are out of Experimental, so an island that uses them can be published. Before 42.40 they were Experimental and not publishable. You can build them on a timeline with animation, Niagara, and sound, and edit the properties in the editor when an effect is selected.

What the notes change:

• Abilities now use entities instead of agents. The notes do not list which members changed. Do not pass an agent where the 42.40 API takes an entity. Look up each call on a 42.40 editor before you edit it.
• If Use fails, the failure is logged.
• fort_ability_attach_socket and fort_target_query_affiliation are now enums. The notes do not list the enumerator names. Do not guess a value or a specifier.
• CentralAngle is renamed Angle on fort_wedge_ability_target_query.
• Angle uses radians, not degrees. See the conversion below.

Behavior the same notes mark as fixed. Drop a matching workaround only after you retest it on 42.40:

• fort_template_ability.Use() with a player as the instigator works.
• Ability animations replicate, and looped animations loop.
• A rejected use no longer runs its full timeline.
• Cancel stops the timeline, and end events no longer fire twice.
• Unequipping mid-use no longer skips end events.
• Targeting queries return entities for players, NPCs, and other actors that have them.
• Fire VFX shows on the player when the burn ability is triggered.

Source: the 42.40 release notes, "Publish Experiences with Custom Abilities".

Convert the wedge Angle to radians

fort_wedge_ability_target_query no longer has CentralAngle. The field is Angle, and the unit is radians.

A degree value left in place is read as radians. Multiply the old degree number by π/180 (about 0.01745).

Old degrees	New radians
45	about 0.7854
90	about 1.5708 (π/2)
180	about 3.1416 (π)

Leaving 90 in the field is about fourteen full turns, not a quarter circle. Rename the field and convert the number in the same edit. These names are from the release notes. Confirm Angle on your 42.40 editor before you delete CentralAngle.

Text chat channels

Verse can create custom text chat channels with text_channel in /Verse.org/Chat. Use it for team, faction, or role chat. Messages show in Fortnite's own chat feed. This is not a custom chat widget. Voice stays on voice_channel in the same module.

The member names in this section are from the 42.40 release notes only. Hosted compile_check does not know them yet. A hosted compile is not proof they exist on your build. Confirm each name in the editor on 42.40 before you ship code that uses it.

From the notes:

Job	Name in the notes
Define a text channel	text_channel
Who may post	CanSend on has_text_member_info
Color and a bracketed label	text_message_style
Default style, or one participant	MessageStyle
Color of system lines	SystemMessageColor
Register or unregister	AddChatChannel(), RemoveChatChannel()
Turn a channel on or off	Enable(), Disable(), IsEnabled()
List channels on this simulation	GetTextChannels()

Rules from the same section:

• A player can be in several channels.
• CanSend false still lets that participant see the others and the text.
• A style change affects new lines only. A contextual label is shown in square brackets after the player name.
• System lines such as "Now chatting in …" and "You cannot write in …" use SystemMessageColor.
• A text channel holds 100 participants. Players past that are left out. Registering fails if the group is already over the limit.
• Parental controls and user settings still apply. Do not promise that every player sees the chat.

The public Chat module page also lists text_channel, has_text_member_info, and text_message_style as of October 15, 2026. That listing is documentation. It does not replace the note above: hosted compile_check does not know these names yet.

Source: the 42.40 release notes, "New Verse API for Text Chat Channels".

VerseVM session toggle

The editor's Session menu has a toggle that sets the VerseVM as the target server for a UEFN session instead of the BPVM. Use it to test an island on the new VM. The roadmap moved the New Virtual Machine card to Q4 2026. The notes do not date a switch.

• Verse Reload is not supported on the VerseVM. It is disabled while the toggle is On.
• Live Edit is only partly supported. Only the BPVM sends Verse properties to the server through Live Edit. With the toggle On, a Live Edit change to a Verse property does not reach the session. Push the Verse changes or relaunch the session.
• A bug you see with the toggle On is a VerseVM result. Retest with it Off before you change code, and say which VM you used.
• The toggle changes the session target. It is not a substitute for a compile.

Source: the 42.40 release notes, "UEFN Updates and Fixes" (the Session toggle) and "Roadmap Updates".

Mobile: Apply Canvas Transform

The Touch Control Layout Override widget has an Apply Canvas Transform property. Use it with Override Touch Controls on a HUD Controller device.

• Unchecked: the override changes only the icon. Position and size overrides are ignored, so each player's own button layout stays as they set it.
• Checked: the override's position and size apply too.

Fixes in the same section, so drop a matching workaround after a retest:

• Override Touch Control Layout works with items that change Jump and Sprint. The notes use the Mandalorian Jetpack as the example: Jump and Sprint switch to Up and Boost.
• Shoot appears when the override references an empty widget.
• Carry/Drop can be overridden and removed.
• Overridden Sprint, Shoot, Reload, and Crouch no longer capture input. Touches pass through to the controls behind them.

This is a device and widget setting in the editor, not Verse. Test it on a touch device.

Source: the 42.40 release notes, "Mobile: HUD Controller and UI Customization".

Known issue: template weapons ghost while aiming

FORT-1173017 is Unconfirmed. Epic created the ticket on October 14, 2026, and queued it to be reproduced. The 42.40 notes do not mention it, and they do not list a fix.

The report is from the day before 42.40 shipped, on Windows. It does not name a build. An Entity Prefab made from an untouched assault_rifle_template, pistol_template, or shotgun_template trails, doubles, or ghosts while aiming down sights and turning the camera quickly. It shows up in a published private or public version launched from Fortnite. The same prefab behaves in a UEFN edit session. A blank island with no custom assets and no Verse reproduces it. Standard Fortnite weapons did not show it in that report. An earlier report on October 9, 2026 describes the same thing with the SMG template.

What the report says did not help: a plain opaque material, other meshes, collision and graphics settings, other entity hierarchies, and a Verse component that kept calling GetLocalTransform() and SetLocalTransform() on the weapon mesh. No workaround is stated.

• An edit-session test does not clear this. Test aiming and fast camera turns in a published private version before you ship a template weapon.
• Do not add a transform-refresh component to fix it. The report tried that, and the published island still ghosted.
• Recheck the ticket status before you treat it as open.

Source: https://forums.unrealengine.com/t/uefn-scene-graph-custom-weapon-entity-prefabs-ghosting-in-published-islands/2840356

Sources

• 42.40 release notes: https://dev.epicgames.com/documentation/fortnite/42-40-fortnite-ecosystem-updates-and-release-notes
• Chat module: https://dev.epicgames.com/documentation/fortnite/verse-api/versedotorg/chat
• text_channel: https://dev.epicgames.com/documentation/fortnite/verse-api/versedotorg/chat/text_channel
• Weapon ghosting report: https://forums.unrealengine.com/t/uefn-scene-graph-custom-weapon-entity-prefabs-ghosting-in-published-islands/2840356