Midnight (Patch 12.0) — What Addon Developers Need to Know¶

Patch 12.0 (Midnight) introduced the largest set of addon API changes since WoW launched. This page covers everything addon developers need to understand: the new combat restrictions, the Secret Values system, deprecated API removals, migration strategies, and how to build addons that thrive under the new rules.

Interface Number¶

Current value for WoW 12.0.1 (Midnight): 120001

Update your .toc file:

## Interface: 120001

The "Skin, Don't Replace" Philosophy¶

Midnight's addon policy can be summarized in one sentence:

Addons can change how information looks, but not what information the player acts on.

Blizzard's design goals:

1. Level the playing field — addons should not provide competitive advantages in combat over players using the default UI.
2. Preserve personalization — visual customization of raid frames, nameplates, action bars, fonts, and art remains fully supported.
3. Combat is a black box — real-time combat data can be displayed by addons but not interpreted for automated decision-making.

This means the era of addons "solving" encounter mechanics (automated rotation helpers, boss callouts with actionable instructions) is over. Addons that skin and restyle the UI continue to work.

Secret Values System¶

Instead of outright removing APIs or moving frames into the secure environment, Blizzard introduced a new technology called Secret Values.

How Secret Values Work¶

• Combat-related data (health changes, damage events, spell casts) is tagged as a secret value.
• Addons can display secret values (bind them to UI elements like health bars, text strings, or progress indicators).
• Addons cannot read, compare, or branch on secret values in Lua logic.

Think of it as a one-way pipe: data flows from the game engine into UI widgets, but addons cannot inspect what's in the pipe.

-- BEFORE Midnight: addons could read and act on combat data
local health = UnitHealth("target")
if health < 1000 then
    -- trigger some automated response
end

-- AFTER Midnight: the value is "secret" in combat contexts
-- You can still bind it to a StatusBar or FontString for display,
-- but conditional logic based on its value is restricted.

What Secret Values Affect¶

COMBAT_LOG_EVENT_UNFILTERED (CLEU) — Removed for Addons¶

The single biggest breaking change in Midnight:

What This Breaks¶

• Boss mods (DBM, BigWigs) — can no longer parse combat events for mechanic detection
• Damage meters (Details!, Recount) — lost granular real-time parsing
• Combat log recorders (Warcraft Logs uploader) — affected but accommodated (see below)
• WeakAuras triggers — combat event-based triggers no longer function
• Threat meters — cannot compute threat from combat events

What Replaces It¶

Blizzard has built native UI systems to replace the most critical addon functionality:

Relaxations for Logging Addons¶

Blizzard acknowledged the initial restrictions were too broad. Combat log data access has been partially restored for post-combat analysis:

• Damage meters can still aggregate and display data, though with less real-time granularity
• CHAT_MSG_ADDON_LOGGED continues to work for combat log recording tools
• Restrictions are tightest during active encounters (raid boss fights, M+ timed runs) and relax between pulls

Spell Whitelist System¶

Not all spell data is equally restricted. Blizzard maintains a whitelist of spells whose state, charges, and cooldowns are fully accessible to addons.

Whitelisted Categories¶

• Class resources that the base UI already tracks (e.g., Enhancement Shaman Maelstrom Weapon stacks, Devoker Demon Hunter Soul Fragments)
• Major cooldowns that Blizzard deems appropriate for addon tracking
• Empowered cast data — number of stages and percentage of cast time per stage have been un-restricted

Requesting Whitelist Additions¶

Blizzard evaluates requests on a case-by-case basis. To request a spell be whitelisted:

1. Post in the UI and Macro forum with a clear justification
2. Explain why addon access to this spell is needed for UI presentation (not competitive advantage)
3. Reference similar whitelisted spells if applicable

Addon Messaging Restrictions in Instances¶

What Changed¶

• During active encounters: addon messaging channels are throttled or blocked to prevent addons from sharing parsed combat data between players
• Between encounters: addon messaging works normally (loot councils, break timers, keystone sharing, raid note distribution)
• Outside instances: no changes

Migration Strategy¶

-- Check if messaging is available before sending
local function SafeSendAddonMessage(prefix, message, channel)
    -- Queue messages during encounters, send after
    if IsEncounterInProgress() then
        -- Store for later
        tinsert(ns.pendingMessages, {prefix, message, channel})
        return false
    end
    C_ChatInfo.SendAddonMessage(prefix, message, channel)
    return true
end

-- Flush pending messages when encounter ends
local frame = CreateFrame("Frame")
frame:RegisterEvent("ENCOUNTER_END")
frame:SetScript("OnEvent", function()
    for _, msg in ipairs(ns.pendingMessages) do
        C_ChatInfo.SendAddonMessage(unpack(msg))
    end
    wipe(ns.pendingMessages)
end)

SendAddonMessage Throttling¶

The existing throttle (10 messages per prefix, regenerating at 1/second) remains, but enforcement is stricter in 12.0. Batch and compress data aggressively:

• Use LibSerialize + LibDeflate for payload compression
• Chunk messages into 255-byte segments with sequence numbers
• Avoid sending redundant data — diff against previously sent state

Deprecated APIs Removed in 12.0¶

All functions deprecated during the 11.x cycle have been fully removed in Patch 12.0.0. If your addon still references any of these, it will error on load.

Removed API Categories¶

Common Migration Examples¶

Spell information:

-- REMOVED in 12.0:
-- local name, rank, icon = GetSpellInfo(spellID)

-- Use instead:
local info = C_Spell.GetSpellInfo(spellID)
if info then
    local name = info.name
    local icon = info.iconID
end

Spell cooldowns:

-- REMOVED in 12.0:
-- local start, duration, enabled = GetSpellCooldown(spellID)

-- Use instead:
local cooldown = C_Spell.GetSpellCooldown(spellID)
if cooldown then
    local start = cooldown.startTime
    local duration = cooldown.duration
end

Addon metadata:

-- Old style (still works but prefer C_ namespace):
-- local version = GetAddOnMetadata("MyAddon", "Version")

-- Preferred:
local version = C_AddOns.GetAddOnMetadata("MyAddon", "Version")

Frame Manipulation Changes¶

The Container Skinning Model¶

Midnight shifts addon UI work toward skinning Blizzard-provided containers rather than creating entirely custom replacements for core UI elements.

What this means in practice:

• Blizzard provides data containers (unit frames, cast bars, nameplate widgets) with structured data bindings
• Addons can restyle these containers: change textures, fonts, sizes, colors, layouts
• Addons should not create wholly independent frames that duplicate Blizzard's data pipelines

-- PREFERRED: Skin an existing Blizzard nameplate
hooksecurefunc("CompactUnitFrame_UpdateAll", function(frame)
    if not frame:IsForbidden() then
        -- Restyle the frame
        frame.healthBar:SetStatusBarTexture("Interface\\AddOns\\MyAddon\\statusbar")
        frame.name:SetFont("Fonts\\FRIZQT__.TTF", 10, "OUTLINE")
    end
end)

-- AVOID: Creating parallel frames that try to read
-- the same data through now-restricted APIs

Protected Frame Changes¶

The rules for secure frame manipulation during combat remain the same but are enforced more strictly in 12.0:

• frame:Show(), frame:Hide(), frame:SetPoint(), frame:SetAttribute() on secure frames remain blocked in combat
• New frames created by addons that interact with combat data may be subject to additional restrictions
• Always use the deferred action pattern (queue changes for PLAYER_REGEN_ENABLED)

Nameplate Customization¶

Nameplates received significant native improvements in Midnight:

• Multiple built-in presets (Classic-inspired, Bold Purple, Modern)
• Native threat visualization (fire effect when pulling aggro)
• Addons can still customize nameplate appearance but with tighter bounds on what data they can read from nameplate units during combat

Updating Existing Addons for Midnight¶

Migration Checklist¶

Use this checklist when updating an addon from 11.x to 12.0:

• [ ] Update ## Interface: to 120001
• [ ] Search for removed API calls — grep your codebase for functions from the removed API list
• [ ] Replace deprecated spell functions — GetSpellInfo() → C_Spell.GetSpellInfo(), etc.
• [ ] Remove CLEU dependencies — any COMBAT_LOG_EVENT_UNFILTERED handlers must be removed or replaced with native UI hooks
• [ ] Audit addon messaging — ensure SendAddonMessage() calls handle in-encounter restrictions gracefully
• [ ] Remove private addon channel usage in instances — private channels in instances are restricted; use "PARTY" or "RAID" channels instead
• [ ] Replace direct frame creation with container skinning — where possible, hook and restyle Blizzard frames rather than creating parallel UI elements
• [ ] Test combat functionality — combat-related features are the most likely to be broken; test in dungeons and raids
• [ ] Check the spell whitelist — if your addon tracks specific spell cooldowns/charges, verify they are whitelisted or request access
• [ ] Test addon communication — verify your addon's messaging works correctly both during and between encounters

Automated API Audit¶

A quick way to find potential issues in your codebase:

# Search for removed/deprecated function calls
grep -rn "GetSpellInfo\|GetSpellCooldown\|CombatLogGetCurrentEventInfo" MyAddon/
grep -rn "COMBAT_LOG_EVENT_UNFILTERED" MyAddon/
grep -rn "GetAddOnMetadata" MyAddon/  # Should use C_AddOns.GetAddOnMetadata

# Search for direct frame manipulation patterns that may need updating
grep -rn "CreateFrame.*SecureActionButtonTemplate" MyAddon/
grep -rn ":SetAttribute(" MyAddon/

Building New Addons for Midnight¶

If you're starting a new addon in 12.0, design around these principles from the start:

1. Skin, Don't Replace¶

Focus on restyling existing Blizzard UI elements rather than building parallel systems:

-- Good: Hook and restyle Blizzard's cast bar
hooksecurefunc(CastingBarFrame, "OnUpdate", function(self)
    -- Customize appearance
end)

-- Avoid: Building your own cast bar that reads spell data directly

2. Focus on Gaps¶

Build in areas Blizzard doesn't natively support well:

• Inventory management — bag sorting, item categorization, equipment sets
• Auction house tools — pricing, batch posting, market analysis
• Social features — guild management, group finding enhancements
• Quality of life — auto-repair, vendor trash selling, coordinate display
• Out-of-combat information — achievement tracking, collection management, transmog tools

3. Use Blizzard Data Containers¶

When you need to display combat-adjacent information, use Blizzard's provided data containers rather than trying to extract raw data:

-- Use Blizzard's StatusBar with built-in data binding
local bar = CreateFrame("StatusBar", nil, parent)
bar:SetMinMaxValues(0, 100)
-- Let Blizzard's systems update the value through proper channels

4. Plan for Combat Lockdown¶

Structure your addon so UI configuration happens entirely outside of combat:

local addonName, ns = ...

function ns:ApplyLayout()
    if InCombatLockdown() then
        ns.layoutPending = true
        return
    end
    -- Do frame positioning, showing/hiding, attribute setting here
end

local frame = CreateFrame("Frame")
frame:RegisterEvent("PLAYER_REGEN_ENABLED")
frame:SetScript("OnEvent", function()
    if ns.layoutPending then
        ns.layoutPending = false
        ns:ApplyLayout()
    end
end)

5. Stay Updated¶

The 12.0.x patch cycle will continue to adjust API restrictions:

• Monitor the Warcraft Wiki API changes page
• Follow the WoW UI and Macro forum
• Join the WoWUIDev Discord for real-time discussion with other addon developers

Stable vs At-Risk API Surfaces¶

Stable — Safe to Build On¶

These APIs are unlikely to see further restrictions in 12.0.x patches:

At-Risk — May Change in 12.0.x Patches¶

These areas have seen iteration during Alpha/Beta and may continue to be adjusted:

Key Resources¶

• Patch 12.0.0/API changes — Warcraft Wiki
• Patch 12.0.0/Planned API changes — Warcraft Wiki
• How Midnight's Changes Impact Combat Addons — Blizzard
• Combat Philosophy and Addon Disarmament — Blizzard
• Midnight UI Updates — Blizzard
• Whitelisted Spells Detailed — Wowhead
• API Change Summaries — Wowpedia