diff --git a/.github/workflows/test-elementpath.yml b/.github/workflows/test-elementpath.yml
index ab2d91c1..9fe9f6a8 100644
--- a/.github/workflows/test-elementpath.yml
+++ b/.github/workflows/test-elementpath.yml
@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.8, 3.9, "3.10", 3.11, 3.12, "3.13.0", "pypy-3.10"]
+        python-version: [3.8, 3.9, "3.10", 3.11, 3.12, "3.13.0", "3.14.0-alpha.1", "pypy-3.10"]
         exclude:
           - os: macos-latest
             python-version: 3.8
@@ -41,10 +41,10 @@ jobs:
           flake8 elementpath --max-line-length=100 --statistics
       - name: Lint with mypy
         run: |
-          pip install mypy==1.11.2 xmlschema lxml-stubs
+          pip install mypy==1.13.0 xmlschema lxml-stubs
           mypy --show-error-codes --strict elementpath
       - name: Install optional dependencies
-        if: ${{ matrix.python-version != '3.13.0' }}
+        if: ${{ matrix.python-version != '3.14.0-alpha.1' }}
         run: pip install lxml
       - name: Test with unittest
         run: |
diff --git a/elementpath/xpath31/_xpath31_functions.py b/elementpath/xpath31/_xpath31_functions.py
index 0ab77ab0..1fac405e 100644
--- a/elementpath/xpath31/_xpath31_functions.py
+++ b/elementpath/xpath31/_xpath31_functions.py
@@ -764,7 +764,8 @@ def decode_value(value: SequenceType[ItemType]) -> ItemType:
         )
 
     def json_object_pairs_to_map(obj: Iterable[Tuple[str, SequenceType[ItemType]]]) -> XPathMap:
-        items = {}
+        items: Dict[ItemType, SequenceType[ItemType]] = {}
+
         for item in obj:
             key, value = decode_value(item[0]), decode_value(item[1])
             if key in items:
diff --git a/tests/test_regex.py b/tests/test_regex.py
index 921a0809..744189bb 100644
--- a/tests/test_regex.py
+++ b/tests/test_regex.py
@@ -704,6 +704,7 @@ def test_others_unicode_blocks(self):
         ncp = len(unicode_block('GreekandCoptic') - unicode_category('Cn'))
         self.assertEqual(ncp, 135)
 
+    @unittest.skipIf(unidata_version[:2] >= '16', f"Unicode {unidata_version} is installed")
     def test_install_unicode_data(self):
         self.assertEqual(unidata_version, unicode_version())
         self.assertNotIn(42971, unicode_category('Ll'))
@@ -734,6 +735,37 @@ def test_install_unicode_data(self):
 
         self.assertEqual(unidata_version, unicode_version())
 
+    @unittest.skipIf(unidata_version[:2] < '16', f"Unicode {unidata_version} is installed")
+    def test_install_previous_unicode_data(self):
+        self.assertEqual(unidata_version, unicode_version())
+        self.assertIn(42971, unicode_category('Ll'))
+
+        install_unicode_data('15.0.0')
+        self.assertEqual('15.0.0', unicode_version())
+        self.assertNotIn(42971, unicode_category('Ll'))
+
+        install_unicode_data()
+        self.assertEqual(unidata_version, unicode_version())
+        self.assertIn(42971, unicode_category('Ll'))
+
+        install_unicode_data('15.0.0', 'elementpath.regex.unicode_categories')
+        self.assertEqual('15.0.0', unicode_version())
+        self.assertNotIn(42971, unicode_category('Ll'))
+
+        install_unicode_data()
+        self.assertEqual(unidata_version, unicode_version())
+        self.assertIn(42971, unicode_category('Ll'))
+
+        with self.assertRaises(ValueError) as ctx:
+            install_unicode_data('14.1.0')
+        self.assertEqual(str(ctx.exception), "argument is not a valid Unicode version")
+
+        with self.assertRaises(TypeError) as ctx:
+            install_unicode_data(name_or_url='elementpath.regex.unicode_categories')
+        self.assertEqual(str(ctx.exception), "you must specify a version to install")
+
+        self.assertEqual(unidata_version, unicode_version())
+
     @unittest.skipUnless('TEST_UNICODE_INSTALLATION' in os.environ,
                          "Skip UnicodeData.txt installation")
     def test_unicode_data_installation_from_source(self):
diff --git a/tox.ini b/tox.ini
index 6d7455c1..d566a2da 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,8 +6,8 @@
 [tox]
 min_version = 4.0
 envlist =
-    py{38,39,310,311,312,313}, pypy3, docs, flake8,
-    mypy-py{38,39,310,311,312,py3}, pytest, coverage,
+    py{38,39,310,311,312,313,314}, pypy3, docs, flake8,
+    mypy-py{38,39,310,311,312,313,py3}, pytest, coverage,
     xmlschema{251,302,310,321,332,342}, w3c-xsdtests
 skip_missing_interpreters = true
 work_dir = {tox_root}/../.tox/elementpath
@@ -23,6 +23,11 @@ set_env =
     py313: TEST_UNICODE_INSTALLATION = 6.2.0
 commands = python -m unittest
 
+[testenv:py314]
+deps =
+    elementpath>=4.4.0, <5.0.0
+    jinja2
+
 [testenv:docs]
 commands =
     make -C doc html SPHINXOPTS="-W -n"
@@ -41,9 +46,9 @@ commands =
     flake8 elementpath
     flake8 tests
 
-[testenv:mypy-py{38,39,310,311,312,py3}]
+[testenv:mypy-py{38,39,310,311,312,313,py3}]
 deps =
-    mypy==1.11.2
+    mypy==1.13.0
     xmlschema>=3.1.0
     lxml-stubs
 commands =