diff --git a/PORTING.md b/PORTING.md
index 362c7f9..a3cec8e 100644
--- a/PORTING.md
+++ b/PORTING.md
@@ -63,18 +63,25 @@ instead.
 Resolve class inside `OnEnable` / event handler, not as a file-level
 `local`.
 
-### CLEU argument positions changed
-Verify against the 3.3.5 signature:
+### CLEU uses the standard WotLK 8-arg signature
+CoA 3.3.5 fires `COMBAT_LOG_EVENT_UNFILTERED` with the plain WotLK layout —
+**no** `hideCaster`, **no** `sourceRaidFlags`/`destRaidFlags` (those are
+Cataclysm+):
 
 ```
-(event, timestamp, subevent, hideCaster,
- srcGUID, srcName, srcFlags, srcRaidFlags,
- destGUID, destName, destFlags, destRaidFlags,
+(event, timestamp, subevent,
+ srcGUID, srcName, srcFlags,
+ destGUID, destName, destFlags,
  spellId, spellName, spellSchool, …)
 ```
 
-`destFlags` is arg 11, not arg 9. Many retail-era addons get this
-wrong.
+`destFlags` is **arg 9**, not arg 11. Do NOT insert the modern
+`hideCaster`/RaidFlags params — doing so shifts everything right, so a
+GUID slot receives a flags *number* and `destGUID:sub(...)` blows up.
+This bit us once: the modern layout was wrongly applied to coa-dbm
+(`UNIT_DIED` crash) and coa-quartz and had to be reverted. If an upstream
+addon's handler reads `(event, ts, subevent, hideCaster, …)`, change it
+back to the 8-arg form for CoA.
 
 ## Ace3 specifics