diff --git a/README.md b/README.md
index 1ce60ea..37b23aa 100644
--- a/README.md
+++ b/README.md
@@ -77,3 +77,6 @@ Textures: CC0
 - 2019-05-01  v1.3  * API function 'compatible_node' added
 - 2019-05-09  v1.4  * Attribute 'tube_type' added
 - 2019-07-12  v1.5  * internal handling of secondary nodes changed
+- 2019-10-25  v1.6  * callback 'tubelib2_on_update2' added
+
+
diff --git a/internal1.lua b/internal1.lua
index c77d2f2..7af35e8 100644
--- a/internal1.lua
+++ b/internal1.lua
@@ -96,8 +96,11 @@ end
 function Tube:update_secondary_node(pos1, dir1, pos2, dir2)
 	local node,_ = self:get_secondary_node(pos1)
 	if node then
-		if (minetest.registered_nodes[node.name] or {}).tubelib2_on_update then
-			minetest.registered_nodes[node.name].tubelib2_on_update(node, pos1, dir1, pos2, Turn180Deg[dir2])			
+		local ndef = minetest.registered_nodes[node.name] or {}
+		if ndef.tubelib2_on_update2 then
+			ndef.tubelib2_on_update2(pos1, dir1, self, node)
+		elseif ndef.tubelib2_on_update then
+			ndef.tubelib2_on_update(node, pos1, dir1, pos2, Turn180Deg[dir2])
 		elseif self.clbk_update_secondary_node then
 			self.clbk_update_secondary_node(node, pos1, dir1, pos2, Turn180Deg[dir2])
 		end
diff --git a/storage.lua b/storage.lua
index 463cedc..bde34a2 100644
--- a/storage.lua
+++ b/storage.lua
@@ -70,6 +70,17 @@ local function unlock(pos)
 	return block, node_key
 end
 
+local function keys_to_pos(block_key, node_key)
+	local f = math.floor
+	block_key = tonumber(block_key) or 0
+	node_key = tonumber(node_key) or 0
+	local x = ((f(block_key % 0x1000) * 0x10) - 32768) + (node_key % 0x10)
+	block_key, node_key = f(block_key / 0x1000), f(node_key / 0x10)
+	local y = ((f(block_key % 0x1000) * 0x10) - 32768) + (node_key % 0x10)
+	block_key, node_key = f(block_key / 0x1000), f(node_key / 0x10)
+	local z = ((f(block_key % 0x1000) * 0x10) - 32768) + (node_key % 0x10)
+	return {x = x, y = y, z = z}
+end
 
 -------------------------------------------------------------------------------
 -- API functions for a node related and high efficient storage table
@@ -99,3 +110,18 @@ function tubelib2.get_mem_data(pos, key, default)
 	return tubelib2.get_mem(pos)[key] or default
 end
 
+function tubelib2.walk_over_all(clbk)
+	local data = storage:to_table()
+	for block_key,sblock in pairs(data.fields) do
+		local block = minetest.deserialize(sblock)
+		for node_key,mem in pairs(block) do
+			if mem then
+				if node_key ~= "used" and node_key ~= "best_before" then
+					local pos = keys_to_pos(block_key, node_key)
+					local node = techage.get_node_lvm(pos)
+					clbk(pos, node, mem)
+				end
+			end
+		end
+	end
+end
diff --git a/tube_api.lua b/tube_api.lua
index 1737e1d..18d9cd7 100644
--- a/tube_api.lua
+++ b/tube_api.lua
@@ -13,7 +13,7 @@
 ]]--
 
 -- Version for compatibility checks, see readme.md/history
-tubelib2.version = 1.4
+tubelib2.version = 1.6
 
 -- for lazy programmers
 local S = function(pos) if pos then return minetest.pos_to_string(pos) end end