diff --git a/invenio_s3/helpers.py b/invenio_s3/helpers.py
index 3eb598b..80da5ff 100644
--- a/invenio_s3/helpers.py
+++ b/invenio_s3/helpers.py
@@ -4,13 +4,14 @@
 #
 # Invenio-S3 is free software; you can redistribute it and/or modify it
 # under the terms of the MIT License; see LICENSE file for more details.
+
 """File serving helpers for S3 files."""
 
 import mimetypes
 import unicodedata
 
 from flask import current_app
-from invenio_files_rest.helpers import chunk_size_or_default, sanitize_mimetype
+from invenio_files_rest.helpers import sanitize_mimetype
 from werkzeug.datastructures import Headers
 from werkzeug.urls import url_quote
 
diff --git a/invenio_s3/storage.py b/invenio_s3/storage.py
index e67e33d..8f31fd6 100644
--- a/invenio_s3/storage.py
+++ b/invenio_s3/storage.py
@@ -4,8 +4,8 @@
 #
 # Invenio-S3 is free software; you can redistribute it and/or modify it
 # under the terms of the MIT License; see LICENSE file for more details.
+
 """S3 file storage interface."""
-from __future__ import absolute_import, division, print_function
 
 from functools import partial, wraps
 from math import ceil
diff --git a/setup.py b/setup.py
index 9cb3ea9..8f2a64d 100644
--- a/setup.py
+++ b/setup.py
@@ -15,8 +15,8 @@
 
 tests_require = [
     'pytest-invenio>=1.4.2',
-    'invenio-base>=1.2.3',
-    'invenio-app>=1.2.3',
+    'invenio-base>=1.2.5',
+    'invenio-app>=1.3.1',
     'invenio-db[all]>=1.0.9',
     'moto>=1.3.7',
     'redis>=2.10.5',
@@ -25,7 +25,7 @@
 extras_require = {
     'docs': [
         'Sphinx>=3.0.1,<3.0.2',
-    ],
+],
     'tests': tests_require,
 }
 
@@ -39,7 +39,7 @@
 
 install_requires = [
     'boto3>=1.9.91,<=1.14.44',
-    'invenio-files-rest>=1.0.0',
+    'invenio-files-rest>=1.3.0',
     's3fs>=0.3.0,<0.4.0',
 ]