ESODecoded

ESO Addons Broken After Update 51? What the API Change Actually Broke

Addons · 6 min · updated 2026-09-28

✓ Current as of Update 51 (2026)⌨ Some tips use add-ons (PC)

The frustration“Update 51 is out and my addons are flagged or throwing errors. Which ones are actually broken?”

Update 51 went live on PC/Mac on 2026-09-28. The game's own API documentation on the live branch now reads API 101051; before it read 101050. Every number below is computed from that documentation and from our addon data, and dated. The short version: the Update 51 removals break almost nothing we can see, the "out of date" label is not the same as broken, and the addons that really are broken were broken before Update 51.

What this page was checked against

The live API version (101051) and the list of removed symbols come from the official ESOUIDocumentation.txt on the esoui/esoui live branch, diffed against the 101050 copy, read 2026-09-28.

Download counts and last-update dates come from the ESOUI feed, retrieved 2026-09-28 (3,231 addons). Each addon's declared APIVersion and the functions its Lua calls come from our own scan of the downloaded addon files, dated 2026-09-28. An addon updated on ESOUI after 2026-09-28 may already have changed both, so the named lists below only include addons whose last ESOUI update is on or before 2026-09-28.

What Update 51 removed from the API

Between API 101050 (Update 50) and API 101051 (Update 51), 27 symbols were removed: 18 functions and 9 constants. A call to a removed function throws a Lua error. A removed constant reads as nil, so a feature can quietly stop instead of erroring.

How many addons call them: 13 of them

We searched the Lua source of the 3,205 addons we have indexed for all 27 removed symbols. 13 of them call at least one.

The limits: that Lua was scanned on 2026-09-28, and addons we have not downloaded are not covered. An addon that shipped a new version after 2026-09-28 was not re-read.

→ Patch radar

What "out of date" means

The label compares one line of each addon's manifest, ## APIVersion, against your client's API number. After Update 51 that number is 101051. Any addon whose manifest names only older versions gets the label, whether or not anything in it broke. ESOUI's out-of-date sticky, verbatim: "Only one line is used to check if 101031 is present in the mods text file." (101031 is that post's own 2021 example.)

There is no checkbox to tick any more. The ESOUI dependency sticky, verbatim: "The checkbox “Allow out of date add-ons” (2, see 1st screenshot above) was removed with the update to Blackwood!" Out-of-date addons load anyway; the game shows a notification once after an API version change.

By the numbers: of the 3,167 addons whose manifest we could read, 251 declare API 101051 or newer and 2,916 declare something older, as of the 2026-09-28 scan. The feed shows 69 addons updated on 2026-09-28, so the real count of current manifests is moving today.

→ ESO Addons "Out of Date" After an Update — What Actually Broke (and What Didn't)

The most-downloaded addons still declaring an older API

These are the 10 most-downloaded non-library addons whose manifest declares an API older than 101051 and that have not been updated on ESOUI since our 2026-09-28 scan. They will show "out of date". That label alone does not mean they are broken; they still load.

The addons that really are broken were broken before Update 51

247 addons in our data call a function or constant that an EARLIER update removed. These are the 10 most-downloaded of them that have not been updated on ESOUI since our 2026-09-28 scan. None of these calls is new with Update 51.

A removed function errors when the code path runs, which may be rare. A removed constant reads as nil. Either way, check the addon's page before replacing it.

→ Check

Fix order

1. Check your client: type /script d(GetAPIVersion()) in chat. On PC/Mac after Update 51 it should print 101051.

2. Update your addons through Minion or from ESOUI. Many authors only bump the APIVersion line, and that alone clears the label.

3. Leave the "out of date" label alone. It is a text comparison and the addon still loads.

4. If an addon says a dependency is missing or disabled, install or enable the library it names. That is the most common real failure after any update.

5. If you get a Lua error popup, find which addon threw it before disabling anything.

6. Treat an addon as broken only when it calls something the game removed. Check it on its addon page or run your whole AddOns folder through our checker.

→ ESO Addon Shows Red "Dependency" and Won't Load — What It Means and How to Fix It→ Which ESO Addon Is Crashing My UI? Read the Error, Then Halve the List→ Which addon

What this page cannot tell youUnverified

We have not decoded the live Update 51 patch notes; our reader was blocked by the forum's bot check. The per-item Update 51 pages come from the PTS patch notes.

Errors caused by changed behaviour rather than removed symbols (a function that still exists but returns something different) do not show up in an API diff.

Consoles follow on ZeniMax's schedule, and console addons are a separate list.

→ U51
Update 51 removed 27 API symbols, and 13 of them of the 3,205 addons we indexed call them. The "out of date" label is a one-line text check. The addons that really fail are the 247 that call something removed earlier, and the fix is an update from the author or a replacement.

Sources & further reading

Related

Update 51: what changedAll 3,231 addons, datedPatch-Break RadarCheck my whole AddOns folderWhich addon is this error?What "out of date" meansRed 'Dependency' fixWhich addon is crashing my UI