diff --git a/common_entities.lua b/common_entities.lua
index 0f6bb64..4c74e7d 100644
--- a/common_entities.lua
+++ b/common_entities.lua
@@ -1,7 +1,7 @@
 --
 -- seat pivot
 --
-minetest.register_entity('airutils:seat_base',{
+core.register_entity('airutils:seat_base',{
 initial_properties = {
 	physical = false,
 	collide_with_objects=false,
@@ -12,13 +12,13 @@ initial_properties = {
 	},
 
     on_activate = function(self,std)
-	    self.sdata = minetest.deserialize(std) or {}
+	    self.sdata = core.deserialize(std) or {}
 	    if self.sdata.remove then self.object:remove() end
     end,
 
     get_staticdata=function(self)
       self.sdata.remove=true
-      return minetest.serialize(self.sdata)
+      return core.serialize(self.sdata)
     end,
 
 })