A player got this message when trying to imp a guard tower. I'm certain I've made & imped many guard towers on 1x servers long before I reached 20 fighting.
Is this a bug, or is it a change to how things work?
If it's a change, I think it makes the game unnecessarily harder on slower servers.
EDIT: to clarify, this is on my own server. I have not modded it so that players can't imp towers.