diff --git a/README.txt b/README.txt
index 79320a1..a1eec4f 100644
--- a/README.txt
+++ b/README.txt
@@ -173,8 +173,9 @@ Minetest 0.4.15+ required
 Installation
 ----------------------
 
-  1) Unzip the archive into the mods directory of your game.
-  2) Rename the doors-master directory to "doors".
+  1) Backup the original "doors" mod to a safe location.
+  2) Unzip the archive into the mods directory of your game.
+  3) Rename the doors-master directory to "doors".
 
 Source code license
 ----------------------------------------------------------
diff --git a/api.lua b/api.lua
index d7685bd..1a822da 100644
--- a/api.lua
+++ b/api.lua
@@ -1,5 +1,5 @@
 --------------------------------------------------------
--- Minetest :: Doors Redux Mod v1.1 (doors)
+-- Minetest :: Doors Redux Mod (doors)
 --
 -- See README.txt for licensing and other information.
 -- Copyright (c) 2016-2020, Leslie E. Krause
@@ -972,3 +972,9 @@ minetest.register_craft( {
 		{ "default:steel_ingot" },
 	}
 } )
+
+-- compatibility for Minetest S3 engine
+
+if not vector.offset_y or not minetest.get_node_above then
+        dofile( minetest.get_modpath( "doors" ) .. "/compatibility.lua" )
+end
diff --git a/init.lua b/init.lua
index 647191b..e6ceffd 100644
--- a/init.lua
+++ b/init.lua
@@ -193,7 +193,9 @@ doors.register_door( "doors:door_mansion1", {
 		{ "group:wood", "group:wood", "default:steel_rod" },
 		{ "group:wood", "group:wood", "dye:white" },
 		{ "group:wood", "group:wood", "default:steel_rod" },
-	}
+	},
+	is_lockable = true,
+	is_closable = true,
 } )
 
 doors.register_door( "doors:door_mansion2", {
@@ -205,7 +207,9 @@ doors.register_door( "doors:door_mansion2", {
 		{ "group:wood", "group:wood", "default:steel_rod" },
 		{ "group:wood", "group:wood", "dye:black" },
 		{ "group:wood", "group:wood", "default:steel_rod" },
-	}
+	},
+	is_lockable = true,
+	is_closable = true,
 } )
 
 doors.register_door( "doors:door_steel", {
@@ -261,7 +265,7 @@ doors.register_door( "doors:door_dungeon2", {
 } )
 
 doors.register_door( "doors:door_steelpanel1", {
-	tiles = {{ name = "doors_door_steelpanel.png", backface_culling = true}},
+	tiles = {{ name = "doors_door_steelpanel1.png", backface_culling = true}},
 	description = "Steel Colonial Door",
 	inventory_image = "doors_item_steelpanel1.png",
 	protected = true,