diff --git a/.github/workflows/test-elementpath.yml b/.github/workflows/test-elementpath.yml
index 0f32ba29..7afbe97d 100644
--- a/.github/workflows/test-elementpath.yml
+++ b/.github/workflows/test-elementpath.yml
@@ -45,7 +45,7 @@ jobs:
         if: ${{ matrix.python-version != '3.7' && matrix.python-version == 'pypy-3.8' }}
         run: |
           pip install mypy==0.950
-          mypy --show-error-codes elementpath
+          mypy --show-error-codes --strict elementpath
       - name: Test with unittest
         run: |
           pip install lxml xmlschema>=1.9.0
diff --git a/elementpath/regex/unicode_subsets.py b/elementpath/regex/unicode_subsets.py
index e545564d..cd1fd29f 100644
--- a/elementpath/regex/unicode_subsets.py
+++ b/elementpath/regex/unicode_subsets.py
@@ -326,7 +326,7 @@ def __eq__(self, other: object) -> bool:
         else:
             return self._codepoints == other
 
-    def __ior__(self, other: object) -> 'UnicodeSubset':  # type: ignore[override]
+    def __ior__(self, other: object) -> 'UnicodeSubset':
         if not isinstance(other, Iterable):
             return NotImplemented
         elif isinstance(other, UnicodeSubset):
@@ -376,7 +376,7 @@ def __and__(self, other: object) -> 'UnicodeSubset':
         obj = self.copy()
         return obj.__iand__(other)
 
-    def __ixor__(self, other: object) -> 'UnicodeSubset':  # type: ignore[override]
+    def __ixor__(self, other: object) -> 'UnicodeSubset':
         if other is self:
             self.clear()
             return self
diff --git a/elementpath/tdop.py b/elementpath/tdop.py
index 8b65d080..b0995c5b 100644
--- a/elementpath/tdop.py
+++ b/elementpath/tdop.py
@@ -357,7 +357,7 @@ def wrong_value(self, message: str = 'invalid value') -> ValueError:
 
 class ParserMeta(ABCMeta):
 
-    token_base_class: Type[Token[Any]]
+    token_base_class: Type[Any]
     literals_pattern: Pattern[str]
     name_pattern: Pattern[str]
     tokenizer: Optional[Pattern[str]]
diff --git a/elementpath/xpath30/xpath30_helpers.py b/elementpath/xpath30/xpath30_helpers.py
index 6f593d4e..9f3be25a 100644
--- a/elementpath/xpath30/xpath30_helpers.py
+++ b/elementpath/xpath30/xpath30_helpers.py
@@ -453,6 +453,9 @@ def parse_datetime_marker(marker: str, dt: datetime.datetime, lang: Optional[str
     else:
         zero_cp, zero_ch = ord('0'), '0'
 
+    min_width: int
+    max_width: Optional[int]
+
     digits = sum(c.isdigit() for c in presentation)
     opt_digits = presentation.count('#')
     if not width or width == '*':
diff --git a/elementpath/xpath_context.py b/elementpath/xpath_context.py
index 80b09b6a..0235369e 100644
--- a/elementpath/xpath_context.py
+++ b/elementpath/xpath_context.py
@@ -12,7 +12,7 @@
 from itertools import chain
 from types import ModuleType
 from typing import TYPE_CHECKING, cast, Dict, Any, List, Iterator, \
-    Optional, Sequence, Union, Callable, MutableMapping, Set, Tuple
+    Optional, Sequence, Union, Callable, MutableMapping, Set
 
 from .exceptions import ElementPathTypeError, ElementPathValueError
 from .namespaces import XML_NAMESPACE
@@ -586,7 +586,7 @@ def iter_descendants(self, axis: Optional[str] = None,
         In this case set the context size at start and change both position and \
         item at each iteration. For default only context item is changed.
         """
-        descendants: Union[Iterator[Union[XPathNodeType, None]], Tuple[XPathNode]]
+        descendants: Any
         with_self = axis != 'descendant'
 
         if self.item is None:
diff --git a/mypy.ini b/mypy.ini
index a0eb185a..7024cfde 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -1,3 +1,2 @@
 [mypy]
 show_error_codes = True
-warn_unused_ignores = True
\ No newline at end of file
diff --git a/tox.ini b/tox.ini
index e5665ad1..b61df1d5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -38,13 +38,20 @@ deps =
 commands =
     flake8 elementpath
 
-[testenv:mypy-py{37,38,39,310}]
+[testenv:mypy-py37]
 deps =
     mypy==0.950
 commands =
     mypy --config-file {toxinidir}/mypy.ini elementpath
     python tests/test_typing.py
 
+[testenv:mypy-py{38,39,310}]
+deps =
+    mypy==0.950
+commands =
+    mypy --config-file {toxinidir}/mypy.ini --strict elementpath
+    python tests/test_typing.py
+
 [testenv:coverage]
 commands =
     coverage run -p -m unittest