diff --git a/django-stubs/contrib/auth/backends.pyi b/django-stubs/contrib/auth/backends.pyi
index 74dcbba..9127221 100644
--- a/django-stubs/contrib/auth/backends.pyi
+++ b/django-stubs/contrib/auth/backends.pyi
@@ -10,9 +10,7 @@ _AnyUser = Union[Model, AnonymousUser]
 UserModel: Any
 
 class BaseBackend:
-    def authenticate(
-        self, request: HttpRequest, username: Optional[str] = ..., password: Optional[str] = ..., **kwargs: Any
-    ) -> Optional[AbstractBaseUser]: ...
+    def authenticate(self, request: Optional[HttpRequest], **kwargs: Any) -> Optional[AbstractBaseUser]: ...
     def get_user(self, user_id: int) -> Optional[AbstractBaseUser]: ...
     def get_user_permissions(self, user_obj: _AnyUser, obj: Optional[Model] = ...) -> Set[str]: ...
     def get_group_permissions(self, user_obj: _AnyUser, obj: Optional[Model] = ...) -> Set[str]: ...
diff --git a/django-stubs/contrib/staticfiles/views.pyi b/django-stubs/contrib/staticfiles/views.pyi
index 8d1ef04..0f5fbb0 100644
--- a/django-stubs/contrib/staticfiles/views.pyi
+++ b/django-stubs/contrib/staticfiles/views.pyi
@@ -1,6 +1,6 @@
 from typing import Any
 
-from django.core.handlers.wsgi import WSGIRequest
+from django.http.request import HttpRequest
 from django.http.response import FileResponse
 
-def serve(request: WSGIRequest, path: str, insecure: bool = ..., **kwargs: Any) -> FileResponse: ...
+def serve(request: HttpRequest, path: str, insecure: bool = ..., **kwargs: Any) -> FileResponse: ...
diff --git a/django-stubs/core/mail/backends/base.pyi b/django-stubs/core/mail/backends/base.pyi
index 7aec2dd..6e73e69 100644
--- a/django-stubs/core/mail/backends/base.pyi
+++ b/django-stubs/core/mail/backends/base.pyi
@@ -1,5 +1,5 @@
 import types
-from typing import Any, Iterable, Optional, Type, TypeVar
+from typing import Any, Optional, Sequence, Type, TypeVar
 
 from django.core.mail.message import EmailMessage
 
@@ -13,4 +13,4 @@ class BaseEmailBackend:
     def __exit__(
         self, exc_type: Type[BaseException], exc_value: BaseException, traceback: types.TracebackType
     ) -> None: ...
-    def send_messages(self, email_messages: Iterable[EmailMessage]) -> int: ...
+    def send_messages(self, email_messages: Sequence[EmailMessage]) -> int: ...
diff --git a/django-stubs/http/response.pyi b/django-stubs/http/response.pyi
index 1c67e5a..ffa44e4 100644
--- a/django-stubs/http/response.pyi
+++ b/django-stubs/http/response.pyi
@@ -101,8 +101,8 @@ class HttpResponse(HttpResponseBase):
 
 class StreamingHttpResponse(HttpResponseBase):
     content: Any
-    streaming_content: Iterator[Any]
-    def __init__(self, streaming_content: Iterable[Any] = ..., *args: Any, **kwargs: Any) -> None: ...
+    streaming_content: Iterator[bytes]
+    def __init__(self, streaming_content: Iterable[bytes] = ..., *args: Any, **kwargs: Any) -> None: ...
     def getvalue(self) -> bytes: ...
 
 class FileResponse(StreamingHttpResponse):