diff --git a/lib/importlib_metadata/__init__.py b/lib/importlib_metadata/__init__.py
index 32ee3b4d..ed481355 100644
--- a/lib/importlib_metadata/__init__.py
+++ b/lib/importlib_metadata/__init__.py
@@ -12,14 +12,13 @@ import inspect
 import pathlib
 import operator
 import textwrap
-import warnings
 import functools
 import itertools
 import posixpath
 import collections
 
-from . import _adapters, _meta
-from .compat import py39
+from . import _meta
+from .compat import py39, py311
 from ._collections import FreezableDefaultDict, Pair
 from ._compat import (
     NullFinder,
@@ -334,27 +333,7 @@ class FileHash:
         return f'<FileHash mode: {self.mode} value: {self.value}>'
 
 
-class DeprecatedNonAbstract:
-    # Required until Python 3.14
-    def __new__(cls, *args, **kwargs):
-        all_names = {
-            name for subclass in inspect.getmro(cls) for name in vars(subclass)
-        }
-        abstract = {
-            name
-            for name in all_names
-            if getattr(getattr(cls, name), '__isabstractmethod__', False)
-        }
-        if abstract:
-            warnings.warn(
-                f"Unimplemented abstract methods {abstract}",
-                DeprecationWarning,
-                stacklevel=2,
-            )
-        return super().__new__(cls)
-
-
-class Distribution(DeprecatedNonAbstract):
+class Distribution(metaclass=abc.ABCMeta):
     """
     An abstract Python distribution package.
 
@@ -461,6 +440,9 @@ class Distribution(DeprecatedNonAbstract):
         Custom providers may provide the METADATA file or override this
         property.
         """
+        # deferred for performance (python/cpython#109829)
+        from . import _adapters
+
         opt_text = (
             self.read_text('METADATA')
             or self.read_text('PKG-INFO')
@@ -567,9 +549,8 @@ class Distribution(DeprecatedNonAbstract):
             return
 
         paths = (
-            (subdir / name)
-            .resolve()
-            .relative_to(self.locate_file('').resolve())
+            py311.relative_fix((subdir / name).resolve())
+            .relative_to(self.locate_file('').resolve(), walk_up=True)
             .as_posix()
             for name in text.splitlines()
         )
diff --git a/lib/importlib_metadata/_adapters.py b/lib/importlib_metadata/_adapters.py
index 120e43a0..6223263e 100644
--- a/lib/importlib_metadata/_adapters.py
+++ b/lib/importlib_metadata/_adapters.py
@@ -1,20 +1,8 @@
-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):
@@ -53,12 +41,17 @@ class Message(email.message.Message):
 
     def __getitem__(self, item):
         """
-        Warn users that a ``KeyError`` can be expected when a
-        missing key is supplied. Ref python/importlib_metadata#371.
+        Override parent behavior to typical dict behavior.
+
+        ``email.message.Message`` will emit None values for missing
+        keys. Typical mappings, including this ``Message``, will raise
+        a key error for missing keys.
+
+        Ref python/importlib_metadata#371.
         """
         res = super().__getitem__(item)
         if res is None:
-            _warn()
+            raise KeyError(item)
         return res
 
     def _repair_headers(self):
diff --git a/lib/importlib_metadata/compat/py311.py b/lib/importlib_metadata/compat/py311.py
new file mode 100644
index 00000000..3a532743
--- /dev/null
+++ b/lib/importlib_metadata/compat/py311.py
@@ -0,0 +1,22 @@
+import os
+import pathlib
+import sys
+import types
+
+
+def wrap(path):  # pragma: no cover
+    """
+    Workaround for https://github.com/python/cpython/issues/84538
+    to add backward compatibility for walk_up=True.
+    An example affected package is dask-labextension, which uses
+    jupyter-packaging to install JupyterLab javascript files outside
+    of site-packages.
+    """
+
+    def relative_to(root, *, walk_up=False):
+        return pathlib.Path(os.path.relpath(path, root))
+
+    return types.SimpleNamespace(relative_to=relative_to)
+
+
+relative_fix = wrap if sys.version_info < (3, 12) else lambda x: x
diff --git a/package/requirements-package.txt b/package/requirements-package.txt
index 85f0e61b..2f21fea4 100644
--- a/package/requirements-package.txt
+++ b/package/requirements-package.txt
@@ -1,5 +1,5 @@
 apscheduler==3.10.1
-importlib-metadata==7.1.0
+importlib-metadata==8.0.0
 importlib-resources==6.4.0
 pyinstaller==6.8.0
 pyopenssl==24.1.0
diff --git a/requirements.txt b/requirements.txt
index c42251a4..f1593fe6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -16,7 +16,7 @@ gntp==1.0.3
 html5lib==1.1
 httpagentparser==1.9.5
 idna==3.7
-importlib-metadata==7.1.0
+importlib-metadata==8.0.0
 importlib-resources==6.4.0
 git+https://github.com/Tautulli/ipwhois.git@master#egg=ipwhois
 IPy==1.01