diff --git a/plugins/VersionUpgrade/VersionUpgrade32to33/VersionUpgrade32to33.py b/plugins/VersionUpgrade/VersionUpgrade32to33/VersionUpgrade32to33.py
index de2240a7c6..620f367e25 100644
--- a/plugins/VersionUpgrade/VersionUpgrade32to33/VersionUpgrade32to33.py
+++ b/plugins/VersionUpgrade/VersionUpgrade32to33/VersionUpgrade32to33.py
@@ -56,6 +56,8 @@ _EXTRUDER_TO_POSITION = {
 ##  Upgrades configurations from the state they were in at version 3.2 to the
 #   state they should be in at version 3.3.
 class VersionUpgrade32to33(VersionUpgrade):
+
+    temporary_group_name_counter = 1
     ##  Gets the version number from a CFG file in Uranium's 3.2 format.
     #
     #   Since the format may change, this is implemented for the 3.2 format only
@@ -74,6 +76,28 @@ class VersionUpgrade32to33(VersionUpgrade):
         setting_version = int(parser.get("metadata", "setting_version", fallback = 0))
         return format_version * 1000000 + setting_version
 
+    ##  Upgrades a container stack from version 3.2 to 3.3.
+    #
+    #   \param serialised The serialised form of a container stack.
+    #   \param filename The name of the file to upgrade.
+    def upgradeStack(self, serialized, filename):
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialized)
+
+        if "metadata" in parser and "um_network_key" in parser["metadata"]:
+            if "hidden" not in parser["metadata"]:
+                parser["metadata"]["hidden"] = "False"
+            if "connect_group_name" not in parser["metadata"]:
+                parser["metadata"]["connect_group_name"] = "Temporary group name #" + str(self.temporary_group_name_counter)
+                self.temporary_group_name_counter += 1
+
+        #Update version number.
+        parser["general"]["version"] = "4"
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]
+
     ##  Upgrades non-quality-changes instance containers to have the new version
     #   number.
     def upgradeInstanceContainer(self, serialized, filename):
diff --git a/plugins/VersionUpgrade/VersionUpgrade32to33/__init__.py b/plugins/VersionUpgrade/VersionUpgrade32to33/__init__.py
index c411b4190e..72ff6e1de9 100644
--- a/plugins/VersionUpgrade/VersionUpgrade32to33/__init__.py
+++ b/plugins/VersionUpgrade/VersionUpgrade32to33/__init__.py
@@ -9,11 +9,22 @@ def getMetaData():
     return {
         "version_upgrade": {
             # From                           To                              Upgrade function
+            ("machine_stack", 3000004):      ("machine_stack", 4000004,      upgrade.upgradeStack),
+            ("extruder_train", 3000004):     ("extruder_train", 4000004,     upgrade.upgradeStack),
+
             ("definition_changes", 2000004): ("definition_changes", 3000004, upgrade.upgradeInstanceContainer),
             ("quality_changes", 2000004):    ("quality_changes", 3000004,    upgrade.upgradeQualityChanges),
             ("user", 2000004):               ("user", 3000004,               upgrade.upgradeInstanceContainer)
         },
         "sources": {
+            "machine_stack": {
+                "get_version": upgrade.getCfgVersion,
+                "location": {"./machine_instances"}
+            },
+            "extruder_train": {
+                "get_version": upgrade.getCfgVersion,
+                "location": {"./extruders"}
+            },
             "definition_changes": {
                 "get_version": upgrade.getCfgVersion,
                 "location": {"./definition_changes"}