diff --git a/scripts/init.lua b/scripts/init.lua
index d7124fc..991499e 100644
--- a/scripts/init.lua
+++ b/scripts/init.lua
@@ -21,8 +21,6 @@ end
 
 
 local function init()
-	global.version = 12 -- important for migrations
-
 	global.random = game.create_random_generator()
 	global.lightEffects = {}
 
diff --git a/scripts/migration.lua b/scripts/migration.lua
index 003ab3e..e81b4e4 100644
--- a/scripts/migration.lua
+++ b/scripts/migration.lua
@@ -7,372 +7,18 @@ local splitty = require(rpath .. "gui.util").splitty
 local Setting = require(rpath .. "setting")
 
 
-local function on_settings_changed()
+local function on_configuration_changed()
 	for _,reactor in pairs(global.reactors) do --updating signals for removed fuel cell mods
 		if reactor.entity.valid == true then
 			if reactor.entity.get_fuel_inventory().is_empty() then
-				reactor.signals.parameters["uranium-fuel-cells"].signal = {type="item", name="uranium-fuel-cell"}
-				reactor.signals.parameters["uranium-fuel-cells"].count = 0
+				reactor.signals.parameters["uranium-fuel-cells"] = {signal=SIGNAL_URANIUM_FUEL_CELLS, count=0, index=8}
 			end
 		end
 		reactor.signals.parameters["used-uranium-fuel-cells"] = nil
-		--if reactor.entity.get_burnt_result_inventory().is_empty() then
-		--	reactor.signals.parameters["used-uranium-fuel-cells"].signal = {type="item", name="used-up-uranium-fuel-cell"}
-		--	reactor.signals.parameters["used-uranium-fuel-cells"].count = 0
-		--end
 		reactor.signals.parameters["neighbour-bonus"] = {signal=SIGNAL_NEIGHBOUR_BONUS, count=0, index=13}
 	end
 	technology.init()
 end
 
 
-
-local function migration()
-	--msg("RealisticReactors - current mod version: "..global.version)
-	--game.players[1].print("on_configuration_changed. global.version: "..global.version)
-	if not global.version or global.version < 1 then
-		for i,reactor in pairs(global.reactors) do
-			reactor.signals.parameters["coolant-temperature"] = nil
-			reactor.signals.parameters["neighbour-bonus"] = nil
-			--fluid signal removal
-			--reactor.signals.parameters["coolant-amount"] = nil
-			
-			if not reactor.efficiency then
-				reactor.efficiency = 100
-			end
-			if not reactor.signals.parameters["power-output"] then
-				reactor.signals.parameters["power-output"] = {signal=SIGNAL_REACTOR_POWER_OUTPUT,count=0,index=7}
-			end
-			if not reactor.signals.parameters["efficiency"] then
-				reactor.signals.parameters["efficiency"] = {signal=SIGNAL_REACTOR_EFFICIENCY,count=0,index=10}
-			end
-			
-			--2
-			reactor.displayer = reactor.core.surface.create_entity{name = "realistic-reactor-normal", position = {reactor.core.position.x, reactor.core.position.y}, force = reactor.core.force.name, create_build_effect_smoke = false}
-			if not reactor.core.get_fuel_inventory().is_empty() then
-				reactor.displayer.get_fuel_inventory().insert(reactor.core.get_fuel_inventory()[1])
-			end
-			
-			--3
-			reactor.fuel_last_tick = reactor.core.burner.remaining_burning_fuel
-			if reactor.core.get_fuel_inventory().is_empty() then
-				reactor.cells_last_tick = 0
-			else
-				reactor.cells_last_tick = reactor.core.get_fuel_inventory()[1].count
-			end
-			reactor.displayer.active = reactor.core.active
-			reactor.displayer.minable = reactor.core.minable
-			
-			--4
-			reactor.power = reactor.core.surface.create_entity{
-				name = REACTOR_POWER_NAME,
-				position = reactor.core.position,
-				force = reactor.core.force,
-				create_build_effect_smoke = false,
-			}
-			reactor.power.destructible=false
-			reactor.power.energy = 17000000
-			reactor.signals.parameters["coolant-amount"] = {signal=SIGNAL_COOLANT_AMOUNT, count=0, index=6}
-			
-			--5 (removed, was the old implementation of bonus cells)
-			--6
-			reactor.signals.parameters["cell-bonus"] = {signal=SIGNAL_REACTOR_CELL_BONUS, count=0, index=11}
-			
-			--7
-			reactor.interface.operable = true
-
-			--8
-			reactor.cooling_history = 0
-			local color = "black"
-			if reactor.state == "starting" then
-				color = "yellow"
-			elseif reactor.state == "running" then
-				color = "green"
-			elseif reactor.state == "scramed" then
-				color = "red"
-			end
-			reactor.lamp = reactor.core.surface.create_entity{name = "rr-"..color.."-lamp", position = {reactor.core.position.x-0.62,reactor.core.position.y+0.6}, force = reactor.core.force.name, create_build_effect_smoke = false}
-			reactor.lamp.destructible = false
-			reactor.light = reactor.core.surface.create_entity{name = "rr-"..color.."-light", position = {reactor.core.position.x-0.62,reactor.core.position.y+0.6}, force = reactor.core.force.name, create_build_effect_smoke = false}
-			reactor.light.destructible = false
-			reactor.interface_warning_tick = 0
-			reactor.interface_warning = nil
-			reactor.cooling_warning_tick = 0
-			reactor.cooling_warning = nil
-			reactor.power_usage = {starting = 0,cooling = 0, interface = 0}
-			reactor.neighbours = 0
-			reactor.bonus_cells = {}
-			reactor.core.destructible = false
-			
-			--9
-			reactor.signals.parameters["electric-power"] = {signal=SIGNAL_REACTOR_ELECTRIC_POWER, count=0, index=12}
-			reactor.fluid_amount_last_tick = 0
-			reactor.power_output_last_tick = 0
-			if reactor.core.get_burnt_result_inventory().is_empty() then
-				reactor.used_cells_last_tick = 0
-			else
-				reactor.used_cells_last_tick = reactor.core.get_burnt_result_inventory()[1].count
-			end
-			
-		end
-		
-		--7
-		gui.init()
-		
-		--9
-		global.fallout = {}
-		global.falloutclouds = {}
-		global.geigers = {}
-		
-
-		
-		global.version=1
-	end
-	
-	if global.version < 2 then
-		
-		--10
-		global.ruins = {}
-		global.sarcophagus = {}
-		game.create_force("radioactivity")
-		game.create_force("radioactivity-strong")
-		
-		--11
-		local reactor_state = {}
-		reactor_state["stopped"] = 0
-		reactor_state["starting"] = 1
-		reactor_state["running"] = 2
-		reactor_state["scramed"] = 3
-		
-		--12
-		global.delayed_fallout={}
-		global.tick_delayer = 0
-		for _, stats in pairs (global.stats) do
-			stats.max = 999
-		end
-		
-		for i,reactor in pairs(global.reactors) do
-			--11
-			reactor.state = reactor_state[reactor.state]
-			reactor.last_temp_update = game.tick
-			reactor.signals.parameters["uranium-fuel-cells"].signal = {type="item", name="uranium-fuel-cell"}
-			--reactor.signals.parameters["used-uranium-fuel-cells"].signal = {type="item", name="used-up-uranium-fuel-cell"}
-			reactor.signals.parameters["used-uranium-fuel-cells"] = nil
-			reactor.core.destructible = false
-			reactor.max_power = 155
-			
-			reactor.interface.destructible = false
-			reactor.interface.minable = false
-		end
-		global.version = 2
-	end
-	
-	if global.version <3 then
-
-		--for _, stats in pairs (global.stats) do
-		--	stats.max = 999
-		--end
-		global.all_heat_pipes = {}
-		global.underground_heat_pipes = {}
-		for _, surface in pairs(game.surfaces) do
-			global.all_heat_pipes[surface.name] = {}
-			local heat_pipes = surface.find_entities_filtered{type='heat-pipe'}
-			
-			for _, hp in pairs (heat_pipes) do
-				if hp.name == "rr-underground-heat-pipe" then
-					table.insert(global.underground_heat_pipes, hp)
-				end
-			--function get_connected_heat_pipes(heat_pipe)
-				local result = {}	
-				
-				for i,heatpipe in pairs(heat_pipes) do
-					
-					if hp.position.x == heatpipe.position.x then
-						if hp.position.y == heatpipe.position.y + 1 or hp.position.y == heatpipe.position.y - 1 then
-							----logging("--> connected to heat pipe, ID: " .. heatpipe.unit_number)
-							table.insert(result, heatpipe)
-						end
-					end
-					
-					if hp.position.y == heatpipe.position.y then
-						if hp.position.x == heatpipe.position.x + 1 or hp.position.x == heatpipe.position.x - 1 then
-							----logging("--> connected to heat pipe, ID: " .. heatpipe.unit_number)
-							table.insert(result, heatpipe)
-						end
-					end		
-					
-				end
-				global.all_heat_pipes[surface.name][hp.unit_number] = {hp,result,{}}
-			end
-		end
-		
-		for i,reactor in pairs(global.reactors) do
-			reactor.max_efficiency = 210
-			local hp_neighbour_entities_ew = reactor.core.surface.find_entities_filtered{area = {{reactor.position.x-2,reactor.position.y-1},{reactor.position.x+2,reactor.position.y}}, type='heat-pipe'} --east and west
-			local hp_neighbour_entities_n = reactor.core.surface.find_entities_filtered{area = {{reactor.position.x-1,reactor.position.y-2},{reactor.position.x+1,reactor.position.y}}, type='heat-pipe'} -- north
-			local table_of_heat_pipes_to_check = union_tables(hp_neighbour_entities_ew,hp_neighbour_entities_n)
-			for _, hp in pairs(table_of_heat_pipes_to_check) do
-				table.insert(global.all_heat_pipes[reactor.core.surface.name][hp.unit_number][3],reactor)
-			end
-				
-		end
-		global.version = 3
-	end
-	
-	if global.version <4 then
-		for i,reactor in pairs(global.reactors) do
-			reactor.last_states_update = game.tick
-		end
-		global.version = 4
-	end
-	
-	if global.version <5 then
-		for key, gui in pairs (global.guis) do
-			if gui.graph then gui.graph.destroy() end
-		end
-		global.version = 5
-	end
-	
-	if global.version <6 then
-		for key, force in pairs (game.forces) do
-			if force.technologies["nuclear-power"].researched then
-				force.recipes["nuclear-reactor"].enabled = true
-			end
-		end
-		global.version = 6
-	end
-	if global.version <7 then
-		for i,reactor in pairs(global.reactors) do
-			reactor.light.teleport{reactor.core.position.x+0.017,reactor.core.position.y+0.88}
-			reactor.lamp.teleport{reactor.core.position.x+0.017,reactor.core.position.y+0.88}
-		end
-		global.version = 7
-	end
-	if global.version <10 then
-		for i,reactor in pairs(global.reactors) do
-			reactor.core.get_fuel_inventory().clear()
-			reactor.core.get_burnt_result_inventory().clear()
-			reactor.core.get_fuel_inventory().insert{name="rr-dummy-fuel-cell", count = 50}
-			reactor.core.burner.currently_burning = "rr-dummy-fuel-cell"
-			reactor.core.burner.remaining_burning_fuel = 9223372035000000000
-		end
-		global.version = 10
-	end
-	if global.version <11 then
-		global.random = game.create_random_generator()
-		global.lightEffects = global.lightEffects or {}
-		global.interfaces = {}
-		network.init()
-
-		local towers = {}
-		global.iterate_cooling_towers = nil -- not needed anymore
-		for _,tower in pairs(global.towers) do
-			if tower.entity.valid then
-				towers[tower.id] = tower -- use unit_number as index
-			end
-		end
-		global.towers = towers
-
-		local ruins = {}
-		for _,ruin in pairs(global.ruins) do
-			if ruin.entity.valid then
-				ruins[ruin.id] = ruin -- use unit_number as index
-				ruin.entity.destructible = false
-				ruin.entity.minable = true
-			end
-		end
-		global.ruins = ruins
-
-		local fallouts = {}
-		for _,fallout in pairs(global.fallout) do
-			if fallout.surface.valid then
-				fallout.id = fallout.surface.index
-				fallout.positions = {[fallout.tick] = fallout.position}
-				fallout.position = nil
-				fallout.tick = nil
-				fallout.clouds = {}
-				fallouts[fallout.id] = fallout -- use surface.index as index
-			end
-		end
-		for _,cloud in pairs(global.falloutclouds) do
-			if cloud.valid then
-				local fallout = fallouts[cloud.surface.index] or {
-					id = cloud.surface.index,
-					surface = cloud.surface,
-					positions = {},
-					clouds = {},
-				}
-				fallouts[fallout.id] = fallout
-				table.insert(fallout.clouds, cloud)
-			end
-		end
-		global.falloutclouds = nil
-		global.fallout = fallouts
-
-		local sarcophagus = {}
-		for _,entity in pairs(global.sarcophagus) do
-			if entity.valid then
-				sarcophagus[entity.unit_number] = entity
-			end
-		end
-		global.sarcophagus = sarcophagus
-
-		local lookup = {}
-		for key,reactor in pairs(global.reactors) do
-			lookup[key] = reactor.displayer.unit_number
-		end
-
-		local reactors = {}
-		global.iterate_reactor_temp_signals = nil
-		global.iterate_reactor_states = nil
-		global.iterate_reactor_temp = nil
-		global.skip_temp_iteration = nil
-		global.tick_delayer = nil
-		for _,reactor in pairs(global.reactors) do
-			if reactor.displayer.valid then
-				reactor.connected_neighbours_IDs = nil
-				reactor.entity = reactor.displayer
-				reactor.displayer = nil
-				reactor.id = reactor.entity.unit_number
-				reactors[reactor.id] = reactor -- use unit_number as index
-			end
-		end
-		global.reactors = reactors
-
-		global.all_heat_pipes = nil
-		global.connected_reactors = nil
-		global.underground_heat_pipes = nil
-
-		local stats = {}
-		for key,stat in pairs(global.stats) do
-			stats[lookup[key]] = stat
-		end
-		global.stats = stats
-
-		local guis = {}
-		global.worker_key = nil
-		for key, gui in pairs(global.guis) do
-			local reactor_key, playerid = splitty(key,"-")
-			if gui.valid then
-				local id = lookup[reactor_key]
-				guis[id .. "-" .. playerid] = gui
-				gui.name = "rr_gui_" .. id
-			end
-		end
-		global.guis = guis
-
-		global.version = 11
-	end
-	if global.version <12 then
-		network.init() -- fixed a bug there, see the π release
-		global.version = 12
-	end
-	--msg("RealisticReactors - current mod version (after migration): "..global.version)
-end
-
-local function on_configuration_changed()
-	migration()
-	on_settings_changed()
-end
-
 return on_configuration_changed -- exports