diff --git a/docs/source/examples.rst b/docs/source/examples.rst
index 538f50d..e0d91d3 100644
--- a/docs/source/examples.rst
+++ b/docs/source/examples.rst
@@ -37,7 +37,7 @@ The following is an example configuration for *Mia! Accounting*.
                 return redirect("/login")
 
             @property
-            def cls(self) -> t.Type[User]:
+            def cls(self) -> type[User]:
                 return User
 
             @property
diff --git a/src/accounting/journal_entry/forms/journal_entry.py b/src/accounting/journal_entry/forms/journal_entry.py
index 839d801..014c3a2 100644
--- a/src/accounting/journal_entry/forms/journal_entry.py
+++ b/src/accounting/journal_entry/forms/journal_entry.py
@@ -19,7 +19,6 @@
 """
 import datetime as dt
 from abc import ABC, abstractmethod
-from typing import Type
 
 import sqlalchemy as sa
 from flask_babel import LazyString
@@ -122,7 +121,7 @@ class JournalEntryForm(FlaskForm):
         super().__init__(*args, **kwargs)
         self.is_modified: bool = False
         """Whether the journal entry is modified during populate_obj()."""
-        self.collector: Type[LineItemCollector] = LineItemCollector
+        self.collector: type[LineItemCollector] = LineItemCollector
         """The line item collector.  The default is the base abstract
         collector only to provide the correct type.  The subclass forms should
         provide their own collectors."""
@@ -153,7 +152,7 @@ class JournalEntryForm(FlaskForm):
         self.__set_date(obj, self.date.data)
         obj.note = self.note.data
 
-        collector_cls: Type[LineItemCollector] = self.collector
+        collector_cls: type[LineItemCollector] = self.collector
         collector: collector_cls = collector_cls(self, obj)
         collector.collect()
 
diff --git a/src/accounting/journal_entry/utils/operators.py b/src/accounting/journal_entry/utils/operators.py
index 57d438a..d132226 100644
--- a/src/accounting/journal_entry/utils/operators.py
+++ b/src/accounting/journal_entry/utils/operators.py
@@ -18,7 +18,6 @@
 
 """
 from abc import ABC, abstractmethod
-from typing import Type
 
 from flask import render_template, request, abort
 from flask_wtf import FlaskForm
@@ -38,7 +37,7 @@ class JournalEntryOperator(ABC):
 
     @property
     @abstractmethod
-    def form(self) -> Type[JournalEntryForm]:
+    def form(self) -> type[JournalEntryForm]:
         """Returns the form class.
 
         :return: The form class.
@@ -99,7 +98,7 @@ class CashReceiptJournalEntry(JournalEntryOperator):
     """The order when checking the journal entry operator."""
 
     @property
-    def form(self) -> Type[JournalEntryForm]:
+    def form(self) -> type[JournalEntryForm]:
         """Returns the form class.
 
         :return: The form class.
@@ -169,7 +168,7 @@ class CashDisbursementJournalEntry(JournalEntryOperator):
     """The order when checking the journal entry operator."""
 
     @property
-    def form(self) -> Type[JournalEntryForm]:
+    def form(self) -> type[JournalEntryForm]:
         """Returns the form class.
 
         :return: The form class.
@@ -242,7 +241,7 @@ class TransferJournalEntry(JournalEntryOperator):
     """The order when checking the journal entry operator."""
 
     @property
-    def form(self) -> Type[JournalEntryForm]:
+    def form(self) -> type[JournalEntryForm]:
         """Returns the form class.
 
         :return: The form class.
diff --git a/src/accounting/models.py b/src/accounting/models.py
index a46022d..090eb8f 100644
--- a/src/accounting/models.py
+++ b/src/accounting/models.py
@@ -22,7 +22,7 @@ from __future__ import annotations
 import datetime as dt
 import re
 from decimal import Decimal
-from typing import Type, Self
+from typing import Self
 
 import sqlalchemy as sa
 from babel import Locale
@@ -269,7 +269,7 @@ class Account(db.Model):
         :return: None.
         """
         AccountL10n.query.filter(AccountL10n.account == self).delete()
-        cls: Type[Self] = self.__class__
+        cls: type[Self] = self.__class__
         cls.query.filter(cls.id == self.id).delete()
 
     @classmethod
@@ -473,7 +473,7 @@ class Currency(db.Model):
         :return: None.
         """
         CurrencyL10n.query.filter(CurrencyL10n.currency == self).delete()
-        cls: Type[Self] = self.__class__
+        cls: type[Self] = self.__class__
         cls.query.filter(cls.code == self.code).delete()
 
 
@@ -815,7 +815,7 @@ class JournalEntryLineItem(db.Model):
         :return: The offset items.
         """
         if not hasattr(self, "__offsets"):
-            cls: Type[Self] = self.__class__
+            cls: type[Self] = self.__class__
             offsets: list[Self] = cls.query.join(JournalEntry)\
                 .filter(JournalEntryLineItem.original_line_item_id == self.id)\
                 .order_by(JournalEntry.date, JournalEntry.no,
diff --git a/src/accounting/report/period/parser.py b/src/accounting/report/period/parser.py
index cbd9c49..2ba5eac 100644
--- a/src/accounting/report/period/parser.py
+++ b/src/accounting/report/period/parser.py
@@ -1,7 +1,7 @@
 # The Mia! Accounting Project.
 # Author: imacat@mail.imacat.idv.tw (imacat), 2023/3/4
 
-#  Copyright (c) 2023 imacat.
+#  Copyright (c) 2023-2026 imacat.
 #
 #  Licensed under the Apache License, Version 2.0 (the "License");
 #  you may not use this file except in compliance with the License.
@@ -21,7 +21,6 @@ import calendar
 import datetime as dt
 import re
 from collections.abc import Callable
-from typing import Type
 
 from .period import Period
 from .shortcuts import ThisMonth, LastMonth, SinceLastMonth, ThisYear, \
@@ -40,7 +39,7 @@ def get_period(spec: str | None = None) -> Period:
     """
     if spec is None:
         return ThisMonth()
-    named_periods: dict[str, Type[Callable[[], Period]]] = {
+    named_periods: dict[str, type[Callable[[], Period]]] = {
         "this-month": lambda: ThisMonth(),
         "last-month": lambda: LastMonth(),
         "since-last-month": lambda: SinceLastMonth(),
diff --git a/src/accounting/report/utils/base_page_params.py b/src/accounting/report/utils/base_page_params.py
index e0b95b2..009522a 100644
--- a/src/accounting/report/utils/base_page_params.py
+++ b/src/accounting/report/utils/base_page_params.py
@@ -19,7 +19,6 @@
 """
 from abc import ABC, abstractmethod
 from collections.abc import Callable
-from typing import Type
 from urllib.parse import urlparse, ParseResult, parse_qsl, urlencode, \
     urlunparse
 
@@ -53,7 +52,7 @@ class BasePageParams(ABC):
         """
 
     @property
-    def journal_entry_types(self) -> Type[JournalEntryType]:
+    def journal_entry_types(self) -> type[JournalEntryType]:
         """Returns the journal entry types.
 
         :return: The journal entry types.
diff --git a/src/accounting/utils/random_id.py b/src/accounting/utils/random_id.py
index e9ec95c..e37ba80 100644
--- a/src/accounting/utils/random_id.py
+++ b/src/accounting/utils/random_id.py
@@ -20,12 +20,11 @@ This module should not import any other module from the application.
 
 """
 from secrets import randbelow
-from typing import Type
 
 from .. import db
 
 
-def new_id(cls: Type[db.Model]):
+def new_id(cls: type[db.Model]):
     """Generates and returns a new, unused random ID for the data model.
 
     :param cls: The data model.
diff --git a/src/accounting/utils/user.py b/src/accounting/utils/user.py
index 646d227..8891d1b 100644
--- a/src/accounting/utils/user.py
+++ b/src/accounting/utils/user.py
@@ -1,7 +1,7 @@
 # The Mia! Accounting Project.
 # Author: imacat@mail.imacat.idv.tw (imacat), 2023/2/1
 
-#  Copyright (c) 2023-2024 imacat.
+#  Copyright (c) 2023-2026 imacat.
 #
 #  Licensed under the Apache License, Version 2.0 (the "License");
 #  you may not use this file except in compliance with the License.
@@ -20,7 +20,6 @@ This module should not import any other module from the application.
 
 """
 from abc import ABC, abstractmethod
-from typing import Type
 
 import sqlalchemy as sa
 from flask import g, Response
@@ -70,7 +69,7 @@ class UserUtilityInterface[T: Model](ABC):
 
     @property
     @abstractmethod
-    def cls(self) -> Type[T]:
+    def cls(self) -> type[T]:
         """Returns the class of the user data model.
 
         :return: The class of the user data model.
diff --git a/tests/test_site/__init__.py b/tests/test_site/__init__.py
index 96b844a..3a020c6 100644
--- a/tests/test_site/__init__.py
+++ b/tests/test_site/__init__.py
@@ -1,7 +1,7 @@
 # The Mia! Accounting Demonstration Website.
 # Author: imacat@mail.imacat.idv.tw (imacat), 2023/1/27
 
-#  Copyright (c) 2023 imacat.
+#  Copyright (c) 2023-2026 imacat.
 #
 #  Licensed under the Apache License, Version 2.0 (the "License");
 #  you may not use this file except in compliance with the License.
@@ -19,7 +19,6 @@
 """
 import os
 from secrets import token_urlsafe
-from typing import Type
 
 from click.testing import Result
 from flask import Flask, Blueprint, render_template, redirect, Response, \
@@ -101,7 +100,7 @@ def create_app(is_testing: bool = False, is_skip_accounts: bool = False,
             return redirect(append_next(url_for("auth.login-form")))
 
         @property
-        def cls(self) -> Type[auth.User]:
+        def cls(self) -> type[auth.User]:
             return auth.User
 
         @property