diff --git a/libs/libpredict.lua b/libs/libpredict.lua
index cbe585f..d54bed6 100644
--- a/libs/libpredict.lua
+++ b/libs/libpredict.lua
@@ -338,13 +338,16 @@ libpredict.sender.SendResCommMsg = function(self, msg)
   SendAddonMessage("CTRA", msg, "BATTLEGROUND")
 end
 
--- tbc
-libpredict.sender:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_START")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_STOP")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_FAILED")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_INTERRUPTED")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_SENT")
+-- tbc (a vanilla client with an API backport such as ClassicAPI fires these
+-- too, next to the vanilla events, without UnitCastingInfo: only tbc listens)
+if GetExpansion() ~= "vanilla" then
+  libpredict.sender:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
+  libpredict.sender:RegisterEvent("UNIT_SPELLCAST_START")
+  libpredict.sender:RegisterEvent("UNIT_SPELLCAST_STOP")
+  libpredict.sender:RegisterEvent("UNIT_SPELLCAST_FAILED")
+  libpredict.sender:RegisterEvent("UNIT_SPELLCAST_INTERRUPTED")
+  libpredict.sender:RegisterEvent("UNIT_SPELLCAST_SENT")
+end
 
 -- vanilla
 libpredict.sender:RegisterEvent("CHAT_MSG_SPELL_SELF_BUFF")