use minetest.settings or fake it if it is not there

mesecons/settings.lua

@@ -1,15 +1,45 @@
 -- SETTINGS
+
+-- legacy:
+minetest.settings = minetest.settings or {
+	get = function(_, k)
+		return minetest.setting_get(k)
+	end,
+	get_bool = function(_, k, default)
+		local s = minetest.setting_getbool(k)
+		if s == nil then
+			s = default
+		end
+		return s
+	end,
+	set = function(_, k, v)
+		return minetest.setting_set(k, v)
+	end,
+	set_bool = function(_, k, v)
+		return minetest.setting_setbool(k, v)
+	end,
+	get_names = function()
+		return {}
+	end,
+	write = function()
+		return minetest.setting_save()
+	end,
+}
+-- do not use get_np_group, set_np_group, remove or to_table
+
+
 function mesecon.setting(setting, default)
 	if type(default) == "boolean" then
-		local read = minetest.setting_getbool("mesecon."..setting)
+		local read = minetest.settings:get_bool("mesecon."..setting, default)
+		 -- legacy:
 		if read == nil then
 			return default
 		else
 			return read
 		end
 	elseif type(default) == "string" then
-		return minetest.setting_get("mesecon."..setting) or default
+		return minetest.settings:get("mesecon."..setting) or default
 	elseif type(default) == "number" then
-		return tonumber(minetest.setting_get("mesecon."..setting) or default)
+		return tonumber(minetest.settings:get("mesecon."..setting) or default)
 	end
 end