diff --git a/npc.lua b/npc.lua
index 01e9251..93b8940 100644
--- a/npc.lua
+++ b/npc.lua
@@ -113,4 +113,5 @@ mobs:register_mob("mobs_npc:npc", {
 
 mobs:register_egg("mobs_npc:npc", "Npc", "default_brick.png", 1)
 
-minetest.register_alias("mobs:npc", "mobs_npc:npc")
+-- compatibility
+mobs:alias_mob("mobs:npc", "mobs_npc:npc")
diff --git a/trader.lua b/trader.lua
index 16b4081..07f8227 100644
--- a/trader.lua
+++ b/trader.lua
@@ -349,4 +349,5 @@ end
 
 mobs:register_egg("mobs_npc:trader", "Trader", "default_sandstone.png", 1)
 
-minetest.register_alias("mobs:trader", "mobs_npc:trader")
+-- compatibility
+mobs:alias_mob("mobs:trader", "mobs_npc:trader")