diff --git a/openslides/users/models.py b/openslides/users/models.py
index 5c4a3c0c4..1e9592a8f 100644
--- a/openslides/users/models.py
+++ b/openslides/users/models.py
@@ -1,5 +1,4 @@
 import smtplib
-
 from random import choice
 
 from django.contrib.auth.hashers import make_password
diff --git a/openslides/utils/autoupdate.py b/openslides/utils/autoupdate.py
index 8926e9400..65aed3244 100644
--- a/openslides/utils/autoupdate.py
+++ b/openslides/utils/autoupdate.py
@@ -3,7 +3,7 @@ import threading
 import time
 import warnings
 from collections import OrderedDict, defaultdict
-from typing import Any, Dict, Generator, Iterable, List, Tuple, Union
+from typing import Any, Dict, Generator, Iterable, List, Optional, Tuple, Union
 
 from channels import Channel, Group
 from channels.asgi import get_channel_layer
@@ -100,7 +100,7 @@ def ws_add_site(message: Any) -> None:
 
                 output.append(formatted_data)
                 # Cache restricted data for user
-                restricted_data_cache.update_element(
+                restricted_data_cache.add_element(
                     user_id,
                     collection.collection_string,
                     data['id'],
@@ -317,12 +317,12 @@ def send_data_site(message: ChannelMessageFormat) -> None:
             send_or_wait(Channel(channel_name).send, {'text': json.dumps(output)})
 
 
-def to_ordered_dict(d):
+def to_ordered_dict(d: Optional[Dict]) -> Optional[OrderedDict]:
     """
     Little helper to hash information dict in inform_*_data.
     """
     if isinstance(d, dict):
-        result = OrderedDict([(key, to_ordered_dict(d[key])) for key in sorted(d.keys())])
+        result = OrderedDict([(key, to_ordered_dict(d[key])) for key in sorted(d.keys())])  # type: Optional[OrderedDict]
     else:
         result = d
     return result
@@ -404,11 +404,11 @@ class AutoupdateBundleMiddleware:
     """
     Middleware to handle autoupdate bundling.
     """
-    def __init__(self, get_response):
+    def __init__(self, get_response: Any) -> None:
         self.get_response = get_response
         # One-time configuration and initialization.
 
-    def __call__(self, request):
+    def __call__(self, request: Any) -> Any:
         thread_id = threading.get_ident()
         autoupdate_bundle[thread_id] = {}
 
diff --git a/openslides/utils/cache.py b/openslides/utils/cache.py
index 1cb16d31f..9e2e6ebc4 100644
--- a/openslides/utils/cache.py
+++ b/openslides/utils/cache.py
@@ -396,6 +396,34 @@ class RestrictedDataCache:
             self.get_cache_key(user_id),
             "{}/{}".format(collection_string, id))
 
+    def del_user(self, user_id: int) -> None:
+        """
+        Removes all elements for one user from the cache.
+        """
+        redis = get_redis_connection()
+        redis.delete(self.get_cache_key(user_id))
+
+    def del_all(self) -> None:
+        """
+        Deletes all elements from the cache.
+
+        This method uses the redis command SCAN. See
+        https://redis.io/commands/scan#scan-guarantees for its limitations. If
+        an element is added to the cache while del_all() is in process, it is
+        possible, that it is not deleted.
+        """
+        redis = get_redis_connection()
+
+        # Get all keys that start with self.base_cache_key and delete them
+        match = cache.make_key('{}:*'.format(self.base_cache_key))
+        cursor = 0
+        while True:
+            cursor, keys = redis.scan(cursor, match)
+            for key in keys:
+                redis.delete(key)
+            if cursor == 0:
+                return
+
     def exists_for_user(self, user_id: int) -> bool:
         """
         Returns True if the cache for the user exists, else False.
diff --git a/openslides/utils/views.py b/openslides/utils/views.py
index 932162202..dc8411ba5 100644
--- a/openslides/utils/views.py
+++ b/openslides/utils/views.py
@@ -85,6 +85,6 @@ class BinaryTemplateView(TemplateView):
     """
     Loads the specified binary template and encode it with base64.
     """
-    def load_template(self):
+    def load_template(self) -> str:
         with open(finders.find(self.template_name), 'rb') as template:
-            return base64.b64encode(template.read())
+            return base64.b64encode(template.read()).decode()
diff --git a/setup.cfg b/setup.cfg
index a07430750..86bcf93e6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -20,10 +20,10 @@ strict_optional = true
 check_untyped_defs = true
 
 [mypy-openslides.utils.*]
-disallow_any = unannotated
+disallow_untyped_defs = true
 
 [mypy-openslides.core.config]
-disallow_any = unannotated
+disallow_untyped_defs = true
 
 [mypy-tests.*]
 ignore_errors = true