what is the unit event for a tower upgradeing to a better tower?

yea, im kinda wondering, almost half of the trigger events in my game are based on this being possible, so i hope it is...

Generic Unit Event - Unit finishes upgrade.

I'm not sure this will work for upgrading towers...

Whats the event response though? as in how do i refer to the upgraded tower? Is it as simple as triggering unit?

make it a tower, with a lv2 upgrade and so on i the object editor

Yes it works for any upgraded unit. The type of unit doesnt matter. Even non buildings. We dont remember the event response for it. We think there is a upgrading unit one. If you cant find one then it would be triggering unit. That wont cause any problems as long as thats the only event your trigger uses.

Make sure you add a condition to specify the type of unit or it will fire on any upgrade.