diff --git a/plugins/VersionUpgrade/VersionUpgrade30to31/VersionUpgrade30to31.py b/plugins/VersionUpgrade/VersionUpgrade30to31/VersionUpgrade30to31.py
index c01ff158b1..8c5a160ff4 100644
--- a/plugins/VersionUpgrade/VersionUpgrade30to31/VersionUpgrade30to31.py
+++ b/plugins/VersionUpgrade/VersionUpgrade30to31/VersionUpgrade30to31.py
@@ -122,21 +122,6 @@ class VersionUpgrade30to31(VersionUpgrade):
             if len(all_quality_changes) <= 1 and not parser.has_option("metadata", "extruder"):
                 self._createExtruderQualityChangesForSingleExtrusionMachine(filename, parser)
 
-        if parser["metadata"]["type"] == "definition_changes":
-            if parser["general"]["definition"] == "custom":
-
-                # We are only interested in machine_nozzle_size
-                if parser.has_option("values", "machine_nozzle_size"):
-                    machine_nozzle_size = parser["values"]["machine_nozzle_size"]
-
-                    definition_name = parser["general"]["name"]
-                    machine_extruders = self._getSingleExtrusionMachineExtruders(definition_name)
-
-                    #For single extuder machine we nee only first extruder
-                    if len(machine_extruders) !=0:
-                        if self._updateSingleExtuderDefinitionFile(machine_extruders, machine_nozzle_size):
-                            parser.remove_option("values", "machine_nozzle_size")
-
         # Update version numbers
         parser["general"]["version"] = "2"
         parser["metadata"]["setting_version"] = "4"
@@ -215,133 +200,6 @@ class VersionUpgrade30to31(VersionUpgrade):
 
         return quality_changes_containers
 
-    def _getSingleExtrusionMachineExtruders(self, definition_name):
-
-        machine_instances_dir = Resources.getPath(CuraApplication.ResourceTypes.MachineStack)
-
-        machine_instances = []
-
-        #Find all machine instances
-        for item in os.listdir(machine_instances_dir):
-            file_path = os.path.join(machine_instances_dir, item)
-            if not os.path.isfile(file_path):
-                continue
-
-            parser = configparser.ConfigParser(interpolation=None)
-            try:
-                parser.read([file_path])
-            except:
-                # skip, it is not a valid stack file
-                continue
-
-            if not parser.has_option("metadata", "type"):
-                continue
-            if "machine" != parser["metadata"]["type"]:
-                continue
-
-            if not parser.has_option("general", "id"):
-                continue
-
-            machine_instances.append(parser)
-
-        #Find for extruders
-        extruders_instances_dir = Resources.getPath(CuraApplication.ResourceTypes.ExtruderStack)
-                    #"machine",[extruders]
-        extruder_instances_per_machine = {}
-
-        #Find all custom extruders for founded machines
-        for item in os.listdir(extruders_instances_dir):
-            file_path = os.path.join(extruders_instances_dir, item)
-            if not os.path.isfile(file_path):
-                continue
-
-            parser = configparser.ConfigParser(interpolation=None)
-            try:
-                parser.read([file_path])
-            except:
-                # skip, it is not a valid stack file
-                continue
-
-            if not parser.has_option("metadata", "type"):
-                continue
-            if "extruder_train" != parser["metadata"]["type"]:
-                continue
-
-            if not parser.has_option("metadata", "machine"):
-                continue
-            if not parser.has_option("metadata", "position"):
-                continue
-
-
-            for machine_instace in machine_instances:
-
-                machine_id = machine_instace["general"]["id"]
-                if machine_id != parser["metadata"]["machine"]:
-                    continue
-
-                if machine_id + "_settings" != definition_name:
-                    continue
-
-                if extruder_instances_per_machine.get(machine_id) is None:
-                    extruder_instances_per_machine.update({machine_id:[]})
-
-                extruder_instances_per_machine.get(machine_id).append(parser)
-                #the extruder can be related only to one machine
-                break
-
-        return extruder_instances_per_machine
-
-    #Find extruder defition at index 0 and update its values
-    def _updateSingleExtuderDefinitionFile(self, extruder_instances_per_machine, machine_nozzle_size):
-
-        defintion_instances_dir = Resources.getPath(CuraApplication.ResourceTypes.DefinitionChangesContainer)
-
-        for item in os.listdir(defintion_instances_dir):
-            file_path = os.path.join(defintion_instances_dir, item)
-            if not os.path.isfile(file_path):
-                continue
-
-            parser = configparser.ConfigParser(interpolation=None)
-            try:
-                parser.read([file_path])
-            except:
-                # skip, it is not a valid stack file
-                continue
-
-            if not parser.has_option("general", "name"):
-                continue
-            name = parser["general"]["name"]
-            custom_extruder_at_0_position = None
-            for machine_extruders in extruder_instances_per_machine:
-                for extruder_instance in extruder_instances_per_machine[machine_extruders]:
-
-                    if extruder_instance["general"]["id"] + "_settings" == name:
-                        defition_position = extruder_instance["metadata"]["position"]
-
-                        if defition_position == "0":
-                            custom_extruder_at_0_position = extruder_instance
-                            break
-                if custom_extruder_at_0_position is not None:
-                    break
-
-            #If not null, then parsed file is for first extuder and then can be updated. I need to update only
-            # first, because this update for single extuder machine
-            if custom_extruder_at_0_position is not None:
-
-                #Add new value
-                parser["values"]["machine_nozzle_size"] = machine_nozzle_size
-
-                definition_output = io.StringIO()
-                parser.write(definition_output)
-
-                with open(file_path, "w") as f:
-                    f.write(definition_output.getvalue())
-
-                return True
-
-        return False
-
-
     def _createExtruderQualityChangesForSingleExtrusionMachine(self, filename, global_quality_changes):
         suffix = "_" + quote_plus(global_quality_changes["general"]["name"].lower())
         machine_name = os.path.os.path.basename(filename).replace(".inst.cfg", "").replace(suffix, "")