diff --git a/update-on-ox b/update-on-ox
index db7e229c11..72072d7d95 100755
--- a/update-on-ox
+++ b/update-on-ox
@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# vim:fileencoding=utf-8
 # License: GPL v3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 import ast
@@ -17,7 +16,7 @@ if False:
     dmg = sys.argv[-1]
     mp = tempfile.mkdtemp()
     atexit.register(os.rmdir, mp)
-    subprocess.check_call('hdiutil attach {} -mountpoint {}'.format(dmg, mp).split())
+    subprocess.check_call(f'hdiutil attach {dmg} -mountpoint {mp}'.split())
     try:
         os.chdir(mp)
         for app in glob.glob('*.app'):
@@ -27,7 +26,7 @@ if False:
             subprocess.check_call('ditto -v {} {}'.format(app, os.path.join('/Applications', app)).split())
     finally:
         os.chdir('/')
-        subprocess.check_call('hdiutil detach {}'.format(mp).split())
+        subprocess.check_call(f'hdiutil detach {mp}'.split())
 
 # EOF_REMOTE