diff --git a/lib/importlib_metadata/__init__.py b/lib/importlib_metadata/__init__.py
index 304b6d48..26a1388c 100644
--- a/lib/importlib_metadata/__init__.py
+++ b/lib/importlib_metadata/__init__.py
@@ -139,6 +139,7 @@ class DeprecatedTuple:
     1
     """
 
+    # Do not remove prior to 2023-05-01 or Python 3.13
     _warn = functools.partial(
         warnings.warn,
         "EntryPoint tuple interface is deprecated. Access members by name.",
@@ -293,8 +294,7 @@ class EntryPoints(tuple):
         Select entry points from self that match the
         given parameters (typically group and/or name).
         """
-        candidates = (_py39compat.ep_matches(ep, **params) for ep in self)
-        return EntryPoints(ep for ep, predicate in candidates if predicate)
+        return EntryPoints(ep for ep in self if _py39compat.ep_matches(ep, **params))
 
     @property
     def names(self):
diff --git a/lib/importlib_metadata/_adapters.py b/lib/importlib_metadata/_adapters.py
index aa460d3e..e33cba5e 100644
--- a/lib/importlib_metadata/_adapters.py
+++ b/lib/importlib_metadata/_adapters.py
@@ -1,8 +1,20 @@
+import functools
+import warnings
 import re
 import textwrap
 import email.message
 
 from ._text import FoldedCase
+from ._compat import pypy_partial
+
+
+# Do not remove prior to 2024-01-01 or Python 3.14
+_warn = functools.partial(
+    warnings.warn,
+    "Implicit None on return values is deprecated and will raise KeyErrors.",
+    DeprecationWarning,
+    stacklevel=pypy_partial(2),
+)
 
 
 class Message(email.message.Message):
@@ -39,6 +51,16 @@ class Message(email.message.Message):
     def __iter__(self):
         return super().__iter__()
 
+    def __getitem__(self, item):
+        """
+        Warn users that a ``KeyError`` can be expected when a
+        mising key is supplied. Ref python/importlib_metadata#371.
+        """
+        res = super().__getitem__(item)
+        if res is None:
+            _warn()
+        return res
+
     def _repair_headers(self):
         def redent(value):
             "Correct for RFC822 indentation"
diff --git a/lib/importlib_metadata/_meta.py b/lib/importlib_metadata/_meta.py
index 37ee43e6..259b15ba 100644
--- a/lib/importlib_metadata/_meta.py
+++ b/lib/importlib_metadata/_meta.py
@@ -30,18 +30,19 @@ class PackageMetadata(Protocol):
         """
 
 
-class SimplePath(Protocol):
+class SimplePath(Protocol[_T]):
     """
     A minimal subset of pathlib.Path required by PathDistribution.
     """
 
-    def joinpath(self) -> 'SimplePath':
+    def joinpath(self) -> _T:
         ...  # pragma: no cover
 
-    def __truediv__(self) -> 'SimplePath':
+    def __truediv__(self, other: Union[str, _T]) -> _T:
         ...  # pragma: no cover
 
-    def parent(self) -> 'SimplePath':
+    @property
+    def parent(self) -> _T:
         ...  # pragma: no cover
 
     def read_text(self) -> str:
diff --git a/lib/importlib_metadata/_py39compat.py b/lib/importlib_metadata/_py39compat.py
index cf9cc124..cde4558f 100644
--- a/lib/importlib_metadata/_py39compat.py
+++ b/lib/importlib_metadata/_py39compat.py
@@ -1,7 +1,7 @@
 """
 Compatibility layer with Python 3.8/3.9
 """
-from typing import TYPE_CHECKING, Any, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Optional
 
 if TYPE_CHECKING:  # pragma: no cover
     # Prevent circular imports on runtime.
@@ -22,27 +22,14 @@ def normalized_name(dist: Distribution) -> Optional[str]:
         return Prepared.normalize(getattr(dist, "name", None) or dist.metadata['Name'])
 
 
-def ep_matches(ep: EntryPoint, **params) -> Tuple[EntryPoint, bool]:
+def ep_matches(ep: EntryPoint, **params) -> bool:
     """
     Workaround for ``EntryPoint`` objects without the ``matches`` method.
-    For the sake of convenience, a tuple is returned containing not only the
-    boolean value corresponding to the predicate evalutation, but also a compatible
-    ``EntryPoint`` object that can be safely used at a later stage.
-
-    For example, the following sequences of expressions should be compatible:
-
-        # Sequence 1: using the compatibility layer
-        candidates = (_py39compat.ep_matches(ep, **params) for ep in entry_points)
-        [ep for ep, predicate in candidates if predicate]
-
-        # Sequence 2: using Python 3.9+
-        [ep for ep in entry_points if ep.matches(**params)]
     """
     try:
-        return ep, ep.matches(**params)
+        return ep.matches(**params)
     except AttributeError:
         from . import EntryPoint  # -> delay to prevent circular imports.
 
         # Reconstruct the EntryPoint object to make sure it is compatible.
-        _ep = EntryPoint(ep.name, ep.value, ep.group)
-        return _ep, _ep.matches(**params)
+        return EntryPoint(ep.name, ep.value, ep.group).matches(**params)
diff --git a/package/requirements-package.txt b/package/requirements-package.txt
index 6260d288..82782772 100644
--- a/package/requirements-package.txt
+++ b/package/requirements-package.txt
@@ -1,5 +1,5 @@
 apscheduler==3.9.1.post1
-importlib-metadata==5.0.0
+importlib-metadata==5.2.0
 importlib-resources==5.10.1
 pyinstaller==5.6.2
 pyopenssl==22.1.0
diff --git a/requirements.txt b/requirements.txt
index cffb49c5..4fc06668 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,7 +18,7 @@ gntp==1.0.3
 html5lib==1.1
 httpagentparser==1.9.5
 idna==3.4
-importlib-metadata==5.0.0
+importlib-metadata==5.2.0
 importlib-resources==5.10.1
 git+https://github.com/Tautulli/ipwhois.git@master#egg=ipwhois
 IPy==1.01