diff --git a/zerver/lib/import_realm.py b/zerver/lib/import_realm.py
index 74cb75ba31..155c8c9e63 100644
--- a/zerver/lib/import_realm.py
+++ b/zerver/lib/import_realm.py
@@ -4,7 +4,6 @@ import os
 import shutil
 from concurrent.futures import ProcessPoolExecutor, as_completed
 from datetime import datetime, timezone
-from mimetypes import guess_type
 from typing import Any, Dict, List, Optional, Set, Tuple
 
 import bmemcached
@@ -28,6 +27,7 @@ from zerver.lib.export import DATE_FIELDS, Field, Path, Record, TableData, Table
 from zerver.lib.markdown import markdown_convert
 from zerver.lib.markdown import version as markdown_version
 from zerver.lib.message import get_last_message_id
+from zerver.lib.mime_types import guess_type
 from zerver.lib.push_notifications import sends_notifications_directly
 from zerver.lib.remote_server import maybe_enqueue_audit_log_upload
 from zerver.lib.server_initialization import create_internal_realm, server_initialized
diff --git a/zerver/lib/mime_types.py b/zerver/lib/mime_types.py
new file mode 100644
index 0000000000..208123eba5
--- /dev/null
+++ b/zerver/lib/mime_types.py
@@ -0,0 +1,14 @@
+import sys
+from mimetypes import add_type
+from mimetypes import guess_type as guess_type
+
+add_type("audio/flac", ".flac")
+add_type("audio/mp4", ".m4a")
+add_type("audio/wav", ".wav")
+add_type("audio/webm", ".weba")
+add_type("image/apng", ".apng")
+
+if sys.version_info < (3, 11):  # nocoverage
+    # https://github.com/python/cpython/issues/89802
+    add_type("image/avif", ".avif")
+    add_type("image/webp", ".webp")
diff --git a/zerver/lib/transfer.py b/zerver/lib/transfer.py
index e80709f28b..a20cfb40bc 100644
--- a/zerver/lib/transfer.py
+++ b/zerver/lib/transfer.py
@@ -1,7 +1,6 @@
 import logging
 import os
 from concurrent.futures import ProcessPoolExecutor, as_completed
-from mimetypes import guess_type
 
 import bmemcached
 from django.conf import settings
@@ -9,6 +8,7 @@ from django.core.cache import cache
 from django.db import connection
 
 from zerver.lib.avatar_hash import user_avatar_path
+from zerver.lib.mime_types import guess_type
 from zerver.lib.upload.s3 import S3UploadBackend, upload_image_to_s3
 from zerver.models import Attachment, RealmEmoji, UserProfile
 
diff --git a/zerver/lib/upload/__init__.py b/zerver/lib/upload/__init__.py
index d41f85fde9..7c2d6755e9 100644
--- a/zerver/lib/upload/__init__.py
+++ b/zerver/lib/upload/__init__.py
@@ -1,7 +1,6 @@
 import io
 import logging
 from datetime import datetime
-from mimetypes import guess_type
 from typing import IO, Any, BinaryIO, Callable, Iterator, List, Optional, Tuple, Union
 from urllib.parse import unquote, urljoin
 
@@ -10,6 +9,7 @@ from django.core.files.uploadedfile import UploadedFile
 from django.utils.translation import gettext as _
 
 from zerver.lib.exceptions import ErrorCode, JsonableError
+from zerver.lib.mime_types import guess_type
 from zerver.lib.outgoing_http import OutgoingSession
 from zerver.lib.upload.base import ZulipUploadBackend
 from zerver.models import Attachment, Message, Realm, RealmEmoji, ScheduledMessage, UserProfile
diff --git a/zerver/lib/upload/s3.py b/zerver/lib/upload/s3.py
index bdbc0083cd..98ed7de301 100644
--- a/zerver/lib/upload/s3.py
+++ b/zerver/lib/upload/s3.py
@@ -2,7 +2,6 @@ import logging
 import os
 import secrets
 from datetime import datetime
-from mimetypes import guess_type
 from typing import IO, Any, BinaryIO, Callable, Iterator, List, Literal, Optional, Tuple
 from urllib.parse import urljoin, urlsplit, urlunsplit
 
@@ -14,6 +13,7 @@ from mypy_boto3_s3.service_resource import Bucket, Object
 from typing_extensions import override
 
 from zerver.lib.avatar_hash import user_avatar_path
+from zerver.lib.mime_types import guess_type
 from zerver.lib.upload.base import (
     INLINE_MIME_TYPES,
     MEDIUM_AVATAR_SIZE,
diff --git a/zerver/views/upload.py b/zerver/views/upload.py
index 07230e0d9f..a33d74f715 100644
--- a/zerver/views/upload.py
+++ b/zerver/views/upload.py
@@ -2,7 +2,6 @@ import base64
 import binascii
 import os
 from datetime import timedelta
-from mimetypes import guess_type
 from typing import List, Optional, Union
 from urllib.parse import quote, urlsplit
 
@@ -28,6 +27,7 @@ from zerver.context_processors import get_valid_realm_from_request
 from zerver.decorator import zulip_redirect_to_login
 from zerver.lib.attachments import validate_attachment_request
 from zerver.lib.exceptions import JsonableError
+from zerver.lib.mime_types import guess_type
 from zerver.lib.response import json_success
 from zerver.lib.storage import static_path
 from zerver.lib.upload import (