diff --git a/installinstallmacos.py b/installinstallmacos.py
index c6b17d6..e6f4d1f 100755
--- a/installinstallmacos.py
+++ b/installinstallmacos.py
@@ -57,7 +57,10 @@ DEFAULT_SUCATALOGS = {
     "index-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
     "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
     "20": "https://swscan.apple.com/content/catalogs/others/"
-    "index-11-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
+    "index-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
+    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
+    "21": "https://swscan.apple.com/content/catalogs/others/"
+    "index-10.16-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
     "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
 }
 
@@ -823,7 +826,9 @@ def main():
         "for the current device.",
     )
     parser.add_argument(
-        "--warnings", action="store_true", help="Show warnings in the listed output",
+        "--warnings",
+        action="store_true",
+        help="Show warnings in the listed output",
     )
     parser.add_argument(
         "--beta",