diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 460fcb5..8f4e670 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -83,10 +83,6 @@ jobs:
       # skipping matrix items that aren't meaningful
       matrix:
         include:
-          - mysql-version: "8.0.32"
-            percona-version: "8.0.32-26-1.focal"
-            python-version: "3.9"
-            ubuntu-version: "20.04"
           - mysql-version: "8.0.32"
             percona-version: "8.0.32-26-1.focal"
             python-version: "3.10"
@@ -99,6 +95,10 @@ jobs:
             percona-version: "8.0.35-30-1.focal"
             python-version: "3.11"
             ubuntu-version: "20.04"
+          - mysql-version: "8.0.35"
+            percona-version: "8.0.35-30-1.focal"
+            python-version: "3.12"
+            ubuntu-version: "20.04"
 
     steps:
       - id: checkout-code
diff --git a/README.md b/README.md
index be71228..40a9529 100644
--- a/README.md
+++ b/README.md
@@ -135,7 +135,7 @@ backed up.
 
 # Requirements
 
-MyHoard requires Python 3.9 or later and some additional components to operate:
+MyHoard requires Python 3.10 or later and some additional components to operate:
 
 - [percona-xtrabackup](https://github.com/percona/percona-xtrabackup)
 - [python3-PyMySQL](https://github.com/PyMySQL/PyMySQL)
diff --git a/myhoard/backup_stream.py b/myhoard/backup_stream.py
index e9ff3ca..81ca7cc 100644
--- a/myhoard/backup_stream.py
+++ b/myhoard/backup_stream.py
@@ -1,6 +1,4 @@
 # Copyright (c) 2019 Aiven, Helsinki, Finland. https://aiven.io/
-from rohmu.errors import FileNotFoundFromStorageError
-
 from .append_only_state_manager import AppendOnlyStateManager
 from .basebackup_operation import BasebackupOperation
 from .binary_io_slice import BinaryIOSlice
@@ -33,11 +31,13 @@
 from rohmu import errors as rohmu_errors
 from rohmu.compressor import CompressionStream
 from rohmu.encryptor import EncryptorStream
+from rohmu.errors import FileNotFoundFromStorageError
 from rohmu.object_storage.s3 import S3Transfer
 from socket import gaierror
 from socks import GeneralProxyError, ProxyConnectionError
 from ssl import SSLEOFError
 from typing import Any, Callable, cast, Dict, Iterable, Iterator, List, Optional, Set, Tuple, TYPE_CHECKING, TypedDict
+
 import contextlib
 import enum
 import json
@@ -256,6 +256,8 @@ def __init__(
             "stream_id": stream_id,
             "updated_at": time.time(),
             "valid_local_binlog_found": False,
+            "number_of_splits": None,
+            "split_size": None,
         }
         self.state_manager = StateManager(lock=self.lock, state=self.state, state_file=state_file)
         self.stats = stats
@@ -672,8 +674,7 @@ def upload_progress(bytes_sent):
             # a separate measurement because uploads are not ongoing all the time and calculating
             # rate based on raw byte counter requires knowing when the operation started and ended
             self.stats.gauge_int(
-                "myhoard.backup_stream.basebackup_bytes_uploaded",
-                self.basebackup_bytes_uploaded + bytes_sent
+                "myhoard.backup_stream.basebackup_bytes_uploaded", self.basebackup_bytes_uploaded + bytes_sent
             )
             last_value[0], last_time[0] = track_rate(
                 current=bytes_sent,
@@ -698,10 +699,7 @@ def upload_progress(bytes_sent):
 
             self.log.info("Uploading basebackup to %s", storage_file_name)
             file_storage.store_file_object(
-                storage_file_name,
-                stream_to_use,
-                metadata=metadata,
-                upload_progress_fn=upload_progress
+                storage_file_name, stream_to_use, metadata=metadata, upload_progress_fn=upload_progress
             )
 
             # Unfortunately, at least for GCP, the upload_progress_fn doesn't get called for the last chunk,
@@ -714,12 +712,14 @@ def upload_progress(bytes_sent):
             if not self.split_size or self.split_size < 1:
                 break
 
-        metadata = make_fs_metadata({
-            **metadata_template,
-            "number_of_splits": split_nr,
-            "split_size": self.split_size,
-            "basebackup_compressed_size": self.basebackup_bytes_uploaded,
-        })
+        metadata = make_fs_metadata(
+            {
+                **metadata_template,
+                "number_of_splits": split_nr,
+                "split_size": self.split_size,
+                "basebackup_compressed_size": self.basebackup_bytes_uploaded,
+            }
+        )
         self.state_manager.update_state(basebackup_file_metadata=metadata)
         self.log.info("Done uploading basebackup files, split into %d files", split_nr)
 
@@ -1265,9 +1265,9 @@ def _upload_binlog(self, binlog: BinlogInfo) -> bool:
                             index_name,
                             encrypt_stream,
                             metadata=metadata,
-                            upload_progress_fn=self.binlog_progress_tracker.increment
-                            if self.binlog_progress_tracker
-                            else None,
+                            upload_progress_fn=(
+                                self.binlog_progress_tracker.increment if self.binlog_progress_tracker else None
+                            ),
                         )
                         self.stats.increase("myhoard.binlog.upload")
                     if self.file_uploaded_callback:
diff --git a/myhoard/basebackup_operation.py b/myhoard/basebackup_operation.py
index efb3183..e2095bf 100644
--- a/myhoard/basebackup_operation.py
+++ b/myhoard/basebackup_operation.py
@@ -1,8 +1,8 @@
 # Copyright (c) 2019 Aiven, Helsinki, Finland. https://aiven.io/
 from contextlib import suppress
-from distutils.version import LooseVersion  # pylint:disable=deprecated-module
 from myhoard.errors import BlockMismatchError, XtraBackupError
 from myhoard.util import get_mysql_version, mysql_cursor
+from packaging.version import Version
 from rohmu.util import increase_pipe_capacity, set_stream_nonblocking
 from typing import Optional
 
@@ -156,7 +156,7 @@ def _optimize_tables(self) -> None:
         params["timeout"] = CURSOR_TIMEOUT_DURING_OPTIMIZE
         with mysql_cursor(**params) as cursor:
             version = get_mysql_version(cursor)
-            if LooseVersion(version) < LooseVersion("8.0.29"):
+            if Version(version) < Version("8.0.29"):
                 return
 
             # allow OPTIMIZE TABLE to run on tables without primary keys
diff --git a/myhoard/binary_io_slice.py b/myhoard/binary_io_slice.py
index 81fb85a..67f4eb8 100644
--- a/myhoard/binary_io_slice.py
+++ b/myhoard/binary_io_slice.py
@@ -1,6 +1,6 @@
 # Copyright (c) 2024 Aiven, Helsinki, Finland. https://aiven.io/
 from types import TracebackType
-from typing import BinaryIO, Type, Iterable, Iterator
+from typing import BinaryIO, Iterable, Iterator, Type
 
 
 class MethodNotSupportedError(Exception):
@@ -14,7 +14,7 @@ def __init__(self, max_file_size: int, stream: BinaryIO):
         self._size_remaining = max_file_size
         self.stream = stream
 
-    def read(self, __n: int = ...) -> bytes:
+    def read(self, __n: int = -1) -> bytes:
         if __n < 0:
             to_read = self._size_remaining
         else:
@@ -53,13 +53,13 @@ def isatty(self) -> bool:
     def readable(self) -> bool:
         return self.stream.readable()
 
-    def readline(self, __limit: int = ...) -> bytes:
+    def readline(self, __limit: int = -1) -> bytes:
         raise MethodNotSupportedError()
 
-    def readlines(self, __hint: int = ...) -> list[bytes]:
+    def readlines(self, __hint: int = -1) -> list[bytes]:
         raise MethodNotSupportedError()
 
-    def seek(self, __offset: int, __whence: int = ...) -> int:
+    def seek(self, __offset: int, __whence: int = 0) -> int:
         return self.stream.seek(__offset, __whence)
 
     def seekable(self) -> bool:
@@ -68,7 +68,7 @@ def seekable(self) -> bool:
     def tell(self) -> int:
         return self._max_file_size - self._size_remaining
 
-    def truncate(self, __size: int | None = ...) -> int:
+    def truncate(self, __size: int | None = None) -> int:
         raise MethodNotSupportedError()
 
     def writable(self) -> bool:
@@ -90,6 +90,6 @@ def __enter__(self) -> BinaryIO:
         return self.stream.__enter__()
 
     def __exit__(
-            self, __t: Type[BaseException] | None, __value: BaseException | None, __traceback: TracebackType | None
+        self, __t: Type[BaseException] | None, __value: BaseException | None, __traceback: TracebackType | None
     ) -> None:
         return self.stream.__exit__(__t, __value, __traceback)
diff --git a/myhoard/restore_coordinator.py b/myhoard/restore_coordinator.py
index d433f56..69b574a 100644
--- a/myhoard/restore_coordinator.py
+++ b/myhoard/restore_coordinator.py
@@ -855,7 +855,7 @@ def _load_file_data(self, name, missing_ok=False):
 
     def _basebackup_data_provider(self, target_stream) -> None:
         compressed_size = self.state["basebackup_info"].get("compressed_size")
-        with (self.file_storage_pool.with_transfer(self.file_storage_config) as file_storage):
+        with self.file_storage_pool.with_transfer(self.file_storage_config) as file_storage:
             last_time = [time.monotonic()]
             last_value = [0]
             self.basebackup_bytes_downloaded = 0
@@ -865,8 +865,9 @@ def _basebackup_data_provider(self, target_stream) -> None:
             def download_progress(progress, max_progress):
                 if progress and max_progress and compressed_size:
                     # progress may be the actual number of bytes or it may be percentages
-                    self.basebackup_bytes_downloaded = total_at_last_split_download[0] \
-                        + int(current_file_size[0] * progress / max_progress)
+                    self.basebackup_bytes_downloaded = total_at_last_split_download[0] + int(
+                        current_file_size[0] * progress / max_progress
+                    )
 
                     # Track both absolute number and explicitly calculated rate. The rate can be useful as
                     # a separate measurement because downloads are not ongoing all the time and calculating
diff --git a/pyproject.toml b/pyproject.toml
index 3623b17..0fdfacd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,16 +10,16 @@ authors = [
 ]
 description = "MyHoard is a daemon for creating, managing and restoring MySQL backups."
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 classifiers=[
     "Development Status :: 5 - Production/Stable",
     "Intended Audience :: Developers",
     "Intended Audience :: Information Technology",
     "Intended Audience :: System Administrators",
     "License :: OSI Approved :: Apache Software License",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
     "Topic :: Database :: Database Engines/Servers",
     "Topic :: Software Development :: Libraries",
 ]
@@ -37,6 +37,7 @@ dependencies = [
     "python-snappy == 0.6.1",
     "rohmu >= 1.1.2",
     "sentry-sdk==1.14.0",
+    "packaging",
 ]
 
 [project.optional-dependencies]
diff --git a/test/test_backup_stream.py b/test/test_backup_stream.py
index 199f0f0..ebb79f0 100644
--- a/test/test_backup_stream.py
+++ b/test/test_backup_stream.py
@@ -1,6 +1,4 @@
 # Copyright (c) 2019 Aiven, Helsinki, Finland. https://aiven.io/
-import rohmu
-
 from . import build_statsd_client, generate_rsa_key_pair, MySQLConfig, wait_for_condition
 from myhoard.backup_stream import BackupStream
 from myhoard.binlog_scanner import BinlogScanner
@@ -13,6 +11,7 @@
 import myhoard.util as myhoard_util
 import os
 import pytest
+import rohmu
 
 pytestmark = [pytest.mark.unittest, pytest.mark.all]
 
@@ -150,6 +149,7 @@ def _run_backup_stream_test(session_tmpdir, mysql_master: MySQLConfig, backup_st
                     "directory": backup_target_location,
                     "storage_type": "local",
                 },
+                "split_size": None,
             }
         }
         backups = Controller.get_backup_list(backup_sites)
diff --git a/test/test_basebackup_operation.py b/test/test_basebackup_operation.py
index 94c9522..51c4258 100644
--- a/test/test_basebackup_operation.py
+++ b/test/test_basebackup_operation.py
@@ -1,7 +1,7 @@
 # Copyright (c) 2019 Aiven, Helsinki, Finland. https://aiven.io/
 from . import build_statsd_client, MySQLConfig, restart_mysql
-from distutils.version import LooseVersion  # pylint:disable=deprecated-module
 from myhoard.basebackup_operation import BasebackupOperation
+from packaging.version import Version
 from typing import IO
 from unittest import SkipTest
 from unittest.mock import mock_open, patch
@@ -139,7 +139,7 @@ def stream_handler(_stream):
 def test_backup_with_non_optimized_tables(mysql_master: MySQLConfig) -> None:
     with myhoard_util.mysql_cursor(**mysql_master.connect_options) as cursor:
         version = myhoard_util.get_mysql_version(cursor)
-        if LooseVersion(version) < LooseVersion("8.0.29"):
+        if Version(version) < Version("8.0.29"):
             raise SkipTest("DB version doesn't need OPTIMIZE TABLE")
 
         def create_test_db(*, db_name: str, table_name: str, add_pk: bool) -> None:
diff --git a/test/test_restore_coordinator.py b/test/test_restore_coordinator.py
index 57bd2b0..eb07644 100644
--- a/test/test_restore_coordinator.py
+++ b/test/test_restore_coordinator.py
@@ -24,7 +24,12 @@ def test_restore_coordinator(session_tmpdir, mysql_master, mysql_empty):
 
 def test_restore_coordinator_with_split_basebackup(session_tmpdir, mysql_master, mysql_empty):
     _restore_coordinator_sequence(
-        session_tmpdir, mysql_master, mysql_empty, pitr=False, rebuild_tables=False, fail_and_resume=False,
+        session_tmpdir,
+        mysql_master,
+        mysql_empty,
+        pitr=False,
+        rebuild_tables=False,
+        fail_and_resume=False,
         split_size=10_000,
     )
 
@@ -48,7 +53,14 @@ def test_restore_coordinator_resume_rebuild_tables(session_tmpdir, mysql_master,
 
 
 def _restore_coordinator_sequence(
-    session_tmpdir, mysql_master, mysql_empty, *, pitr: bool, rebuild_tables: bool, fail_and_resume: bool, split_size: int=0,
+    session_tmpdir,
+    mysql_master,
+    mysql_empty,
+    *,
+    pitr: bool,
+    rebuild_tables: bool,
+    fail_and_resume: bool,
+    split_size: int = 0,
 ):
     with myhoard_util.mysql_cursor(**mysql_master.connect_options) as cursor:
         cursor.execute("CREATE DATABASE db1")
@@ -428,6 +440,7 @@ def test_empty_last_relay(running_state, session_tmpdir, mysql_master, mysql_emp
 
 
 def test_restore_coordinator_check_parameter_before_restart(session_tmpdir):
+    # pylint: disable=W0212,W0108
     restarts = []
 
     state_file = os.path.join(session_tmpdir().strpath, "the_state_file.json")
@@ -436,10 +449,8 @@ def _register_restart(**kwargs):
         restarts.append({**kwargs})
 
     rc = RestoreCoordinator(
-        binlog_streams=[
-        ],
-        file_storage_config={
-        },
+        binlog_streams=[],
+        file_storage_config={},
         free_memory_percentage=80,
         mysql_client_params={},
         mysql_config_file_name="",