diff --git a/dangerzone/cli.py b/dangerzone/cli.py
index 79ab9c3..2b7941b 100644
--- a/dangerzone/cli.py
+++ b/dangerzone/cli.py
@@ -23,7 +23,7 @@ def cli_main(output_filename, ocr_lang, filename):
     global_common = GlobalCommon()
     common = Common()
 
-    global_common.display_banner()
+    GlobalCommon.display_banner()
 
     # Validate filename
     valid = True
@@ -85,7 +85,7 @@ def cli_main(output_filename, ocr_lang, filename):
             return
 
     # Ensure container is installed
-    global_common.install_container()
+    GlobalCommon.install_container()
 
     # Convert the document
     print_header("Converting document to safe PDF")
diff --git a/dangerzone/container.py b/dangerzone/container.py
index 7ad0724..dd628d7 100644
--- a/dangerzone/container.py
+++ b/dangerzone/container.py
@@ -42,7 +42,7 @@ def convert(input_filename, output_filename, ocr_lang, stdout_callback):
     else:
         ocr = "0"
 
-    dz_tmp = os.path.join(appdirs.user_config_dir("dangerzone"), "tmp")
+    dz_tmp = os.path.join(dzutil.APPDATA_PATH, "tmp")
     os.makedirs(dz_tmp, exist_ok=True)
 
     tmpdir = tempfile.TemporaryDirectory(dir=dz_tmp)
diff --git a/dangerzone/global_common.py b/dangerzone/global_common.py
index e11072e..25a07d9 100644
--- a/dangerzone/global_common.py
+++ b/dangerzone/global_common.py
@@ -14,15 +14,14 @@ class GlobalCommon(object):
     """
 
     def __init__(self):
-        self.version = dzutil.VERSION
-
         # Initialize terminal colors
         colorama.init(autoreset=True)
 
         # Load settings
         self.settings = Settings()
 
-    def display_banner(self):
+    @staticmethod
+    def display_banner():
         """
         Raw ASCII art example:
         ╭──────────────────────────╮
diff --git a/dangerzone/gui/application.py b/dangerzone/gui/application.py
index 565ae2e..cff8dd8 100644
--- a/dangerzone/gui/application.py
+++ b/dangerzone/gui/application.py
@@ -1,9 +1,9 @@
-import sys
-
 from PySide6 import QtCore
 from PySide6.QtCore import QEvent
 from PySide6.QtWidgets import QApplication
 
+import dangerzone.util as dzutil
+
 
 class Application(QApplication):
     document_selected = QtCore.Signal(str)
@@ -19,7 +19,7 @@ class Application(QApplication):
             # In macOS, handle the file open event
             if event.type() == QtCore.QEvent.FileOpen:
                 # Skip file open events in dev mode
-                if not hasattr(sys, "dangerzone_dev"):
+                if not dzutil.dev_mode():
                     self.document_selected.emit(event.file())
                     return True
             elif event.type() == QtCore.QEvent.ApplicationActivate:
diff --git a/dangerzone/util.py b/dangerzone/util.py
index 4835fb1..b77cd9b 100644
--- a/dangerzone/util.py
+++ b/dangerzone/util.py
@@ -1,12 +1,22 @@
+from __future__ import annotations
+
 import inspect
 import os
+import pathlib
 import platform
 import shutil
 import subprocess
 import sys
 import appdirs
 
-# If a general-purpose function doesn't depend on anything else in the dangerzone package, then it belongs here.
+# If a general-purpose function or constant doesn't depend on anything else in the dangerzone package,
+# then it belongs here.
+
+SYSTEM = platform.system()
+
+
+def dev_mode() -> bool:
+    return hasattr(sys, "dangerzone_dev")
 
 
 def get_resource_path(filename):
@@ -35,7 +45,7 @@ def get_resource_path(filename):
 
 
 def get_subprocess_startupinfo():
-    if platform.system() == "Windows":
+    if SYSTEM == "Windows":
         startupinfo = subprocess.STARTUPINFO()
         startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
         return startupinfo
@@ -44,7 +54,7 @@ def get_subprocess_startupinfo():
 
 
 def _get_version() -> str:
-    """Dangerzone version number. Prefer dangerzone.VERSION to this function."""
+    """Dangerzone version number. Prefer VERSION to this function."""
     try:
         with open(get_resource_path("version.txt")) as f:
             version = f.read().strip()
@@ -57,7 +67,6 @@ def _get_version() -> str:
 
 VERSION = _get_version()
 APPDATA_PATH = appdirs.user_config_dir("dangerzone")
-SYSTEM = platform.system()
 CONTAINER_NAME = "dangerzone.rocks/dangerzone"
 CONTAINER_COMMAND = "podman" if SYSTEM == "Linux" else "docker"
 CONTAINER_RUNTIME = shutil.which(CONTAINER_COMMAND)