diff --git a/b_asic/scheduler_gui/main_window.py b/b_asic/scheduler_gui/main_window.py
index 8ba117c3e27c339dcd8486f4a9c79dffba4ed2d4..e4381b09f17471e29c70debde880fc511e1223bf 100644
--- a/b_asic/scheduler_gui/main_window.py
+++ b/b_asic/scheduler_gui/main_window.py
@@ -14,7 +14,7 @@ import webbrowser
 from collections import defaultdict, deque
 from copy import deepcopy
 from importlib.machinery import SourceFileLoader
-from typing import TYPE_CHECKING, Deque, List, Optional, cast, overload
+from typing import TYPE_CHECKING, Deque, Dict, List, Optional, cast, overload
 
 # Qt/qtpy
 import qtpy
@@ -126,8 +126,8 @@ class ScheduleMainWindow(QMainWindow, Ui_MainWindow):
     _splitter_pos: int
     _splitter_min: int
     _zoom: float
-    _color_per_type: dict[str, QColor] = dict()
-    converted_colorPerType: dict[str, str] = dict()
+    _color_per_type: Dict[str, QColor] = dict()
+    converted_colorPerType: Dict[str, str] = dict()
 
     def __init__(self):
         """Initialize Scheduler-GUI."""
@@ -148,7 +148,7 @@ class ScheduleMainWindow(QMainWindow, Ui_MainWindow):
         self._execution_time_plot_dialogs = defaultdict(lambda: None)
         self._ports_accesses_for_storage = None
         self._color_changed_perType = False
-        self.changed_operation_colors: dict[str, QColor] = dict()
+        self.changed_operation_colors: Dict[str, QColor] = dict()
 
         # Recent files
         self._max_recent_files = 4