diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index c5ac2a800223b..a6d9e079b26fe 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -85,7 +85,7 @@ See :ref:`install.dependencies` and :ref:`install.optional_dependencies` for mor
 Other API changes
 ^^^^^^^^^^^^^^^^^
 - 3rd party ``py.path`` objects are no longer explicitly supported in IO methods. Use :py:class:`pathlib.Path` objects instead (:issue:`57091`)
--
+- pickled objects from pandas version less than ``1.0.0`` or Python versions less than or equal to ``2.7`` are no longer supported (:issue:`57155`)
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_300.deprecations:
diff --git a/pandas/_libs/tslibs/nattype.pyx b/pandas/_libs/tslibs/nattype.pyx
index cd5e6e521b79f..7a08e4ad4b260 100644
--- a/pandas/_libs/tslibs/nattype.pyx
+++ b/pandas/_libs/tslibs/nattype.pyx
@@ -76,7 +76,7 @@ cdef _nat_rdivide_op(self, other):
     return NotImplemented
 
 
-def __nat_unpickle(*args):
+def _nat_unpickle(*args):
     # return constant defined in the module
     return c_NaT
 
@@ -360,7 +360,7 @@ class NaTType(_NaT):
         return self.__reduce__()
 
     def __reduce__(self):
-        return (__nat_unpickle, (None, ))
+        return (_nat_unpickle, (None, ))
 
     def __rtruediv__(self, other):
         return _nat_rdivide_op(self, other)
diff --git a/pandas/compat/pickle_compat.py b/pandas/compat/pickle_compat.py
index ff589ebba4cf6..012a53789d76a 100644
--- a/pandas/compat/pickle_compat.py
+++ b/pandas/compat/pickle_compat.py
@@ -1,12 +1,12 @@
 """
-Support pre-0.12 series pickle compatibility.
+Pickle compatibility to pandas version 1.0
 """
 from __future__ import annotations
 
 import contextlib
-import copy
+import copyreg
 import io
-import pickle as pkl
+import pickle
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -17,7 +17,6 @@
 from pandas._libs.arrays import NDArrayBacked
 from pandas._libs.tslibs import BaseOffset
 
-from pandas import Index
 from pandas.core.arrays import (
     DatetimeArray,
     PeriodArray,
@@ -29,111 +28,19 @@
     from collections.abc import Generator
 
 
-def load_reduce(self) -> None:
-    stack = self.stack
-    args = stack.pop()
-    func = stack[-1]
-
-    try:
-        stack[-1] = func(*args)
-        return
-    except TypeError as err:
-        # If we have a deprecated function,
-        # try to replace and try again.
-
-        msg = "_reconstruct: First argument must be a sub-type of ndarray"
-
-        if msg in str(err):
-            try:
-                cls = args[0]
-                stack[-1] = object.__new__(cls)
-                return
-            except TypeError:
-                pass
-        elif args and isinstance(args[0], type) and issubclass(args[0], BaseOffset):
-            # TypeError: object.__new__(Day) is not safe, use Day.__new__()
-            cls = args[0]
-            stack[-1] = cls.__new__(*args)
-            return
-        elif args and issubclass(args[0], PeriodArray):
-            cls = args[0]
-            stack[-1] = NDArrayBacked.__new__(*args)
-            return
-
-        raise
-
-
 # If classes are moved, provide compat here.
 _class_locations_map = {
-    ("pandas.core.sparse.array", "SparseArray"): ("pandas.core.arrays", "SparseArray"),
-    # 15477
-    ("pandas.core.base", "FrozenNDArray"): ("numpy", "ndarray"),
     # Re-routing unpickle block logic to go through _unpickle_block instead
     # for pandas <= 1.3.5
     ("pandas.core.internals.blocks", "new_block"): (
         "pandas._libs.internals",
         "_unpickle_block",
     ),
-    ("pandas.core.indexes.frozen", "FrozenNDArray"): ("numpy", "ndarray"),
-    ("pandas.core.base", "FrozenList"): ("pandas.core.indexes.frozen", "FrozenList"),
-    # 10890
-    ("pandas.core.series", "TimeSeries"): ("pandas.core.series", "Series"),
-    ("pandas.sparse.series", "SparseTimeSeries"): (
-        "pandas.core.sparse.series",
-        "SparseSeries",
-    ),
-    # 12588, extensions moving
-    ("pandas._sparse", "BlockIndex"): ("pandas._libs.sparse", "BlockIndex"),
-    ("pandas.tslib", "Timestamp"): ("pandas._libs.tslib", "Timestamp"),
-    # 18543 moving period
-    ("pandas._period", "Period"): ("pandas._libs.tslibs.period", "Period"),
-    ("pandas._libs.period", "Period"): ("pandas._libs.tslibs.period", "Period"),
-    # 18014 moved __nat_unpickle from _libs.tslib-->_libs.tslibs.nattype
-    ("pandas.tslib", "__nat_unpickle"): (
-        "pandas._libs.tslibs.nattype",
-        "__nat_unpickle",
-    ),
-    ("pandas._libs.tslib", "__nat_unpickle"): (
+    ("pandas._libs.tslibs.nattype", "__nat_unpickle"): (
         "pandas._libs.tslibs.nattype",
-        "__nat_unpickle",
-    ),
-    # 15998 top-level dirs moving
-    ("pandas.sparse.array", "SparseArray"): (
-        "pandas.core.arrays.sparse",
-        "SparseArray",
+        "_nat_unpickle",
     ),
-    ("pandas.indexes.base", "_new_Index"): ("pandas.core.indexes.base", "_new_Index"),
-    ("pandas.indexes.base", "Index"): ("pandas.core.indexes.base", "Index"),
-    ("pandas.indexes.numeric", "Int64Index"): (
-        "pandas.core.indexes.base",
-        "Index",  # updated in 50775
-    ),
-    ("pandas.indexes.range", "RangeIndex"): ("pandas.core.indexes.range", "RangeIndex"),
-    ("pandas.indexes.multi", "MultiIndex"): ("pandas.core.indexes.multi", "MultiIndex"),
-    ("pandas.tseries.index", "_new_DatetimeIndex"): (
-        "pandas.core.indexes.datetimes",
-        "_new_DatetimeIndex",
-    ),
-    ("pandas.tseries.index", "DatetimeIndex"): (
-        "pandas.core.indexes.datetimes",
-        "DatetimeIndex",
-    ),
-    ("pandas.tseries.period", "PeriodIndex"): (
-        "pandas.core.indexes.period",
-        "PeriodIndex",
-    ),
-    # 19269, arrays moving
-    ("pandas.core.categorical", "Categorical"): ("pandas.core.arrays", "Categorical"),
-    # 19939, add timedeltaindex, float64index compat from 15998 move
-    ("pandas.tseries.tdi", "TimedeltaIndex"): (
-        "pandas.core.indexes.timedeltas",
-        "TimedeltaIndex",
-    ),
-    ("pandas.indexes.numeric", "Float64Index"): (
-        "pandas.core.indexes.base",
-        "Index",  # updated in 50775
-    ),
-    # 50775, remove Int64Index, UInt64Index & Float64Index from codabase
+    # 50775, remove Int64Index, UInt64Index & Float64Index from codebase
     ("pandas.core.indexes.numeric", "Int64Index"): (
         "pandas.core.indexes.base",
         "Index",
@@ -153,20 +60,29 @@ def load_reduce(self) -> None:
 }
 
 
-# our Unpickler sub-class to override methods and some dispatcher
-# functions for compat and uses a non-public class of the pickle module.
-
+def load_reduce(self):
+    stack = self.stack
+    args = stack.pop()
+    func = stack[-1]
 
-class Unpickler(pkl._Unpickler):
-    def find_class(self, module, name):
-        # override superclass
-        key = (module, name)
-        module, name = _class_locations_map.get(key, key)
-        return super().find_class(module, name)
+    try:
+        stack[-1] = func(*args)
+        return
+    except TypeError:
+        # If we have a deprecated function,
+        # try to replace and try again.
 
+        if args and isinstance(args[0], type) and issubclass(args[0], BaseOffset):
+            # TypeError: object.__new__(Day) is not safe, use Day.__new__()
+            cls = args[0]
+            stack[-1] = cls.__new__(*args)
+            return
+        elif args and issubclass(args[0], PeriodArray):
+            cls = args[0]
+            stack[-1] = NDArrayBacked.__new__(*args)
+            return
 
-Unpickler.dispatch = copy.copy(Unpickler.dispatch)
-Unpickler.dispatch[pkl.REDUCE[0]] = load_reduce
+        raise
 
 
 def load_newobj(self) -> None:
@@ -174,9 +90,7 @@ def load_newobj(self) -> None:
     cls = self.stack[-1]
 
     # compat
-    if issubclass(cls, Index):
-        obj = object.__new__(cls)
-    elif issubclass(cls, DatetimeArray) and not args:
+    if issubclass(cls, DatetimeArray) and not args:
         arr = np.array([], dtype="M8[ns]")
         obj = cls.__new__(cls, arr, arr.dtype)
     elif issubclass(cls, TimedeltaArray) and not args:
@@ -190,29 +104,18 @@ def load_newobj(self) -> None:
     self.stack[-1] = obj
 
 
-Unpickler.dispatch[pkl.NEWOBJ[0]] = load_newobj
-
-
-def load_newobj_ex(self) -> None:
-    kwargs = self.stack.pop()
-    args = self.stack.pop()
-    cls = self.stack.pop()
-
-    # compat
-    if issubclass(cls, Index):
-        obj = object.__new__(cls)
-    else:
-        obj = cls.__new__(cls, *args, **kwargs)
-    self.append(obj)
-
+class Unpickler(pickle.Unpickler):
+    dispatch_table = copyreg.dispatch_table.copy()
+    dispatch_table[pickle.REDUCE[0]] = load_reduce
+    dispatch_table[pickle.NEWOBJ[0]] = load_newobj
 
-try:
-    Unpickler.dispatch[pkl.NEWOBJ_EX[0]] = load_newobj_ex
-except (AttributeError, KeyError):
-    pass
+    def find_class(self, module, name):
+        key = (module, name)
+        module, name = _class_locations_map.get(key, key)
+        return super().find_class(module, name)
 
 
-def load(fh, encoding: str | None = None, is_verbose: bool = False) -> Any:
+def load(fh, encoding: str | None = None) -> Any:
     """
     Load a pickle, with a provided encoding,
 
@@ -220,20 +123,13 @@ def load(fh, encoding: str | None = None, is_verbose: bool = False) -> Any:
     ----------
     fh : a filelike object
     encoding : an optional encoding
-    is_verbose : show exception output
     """
-    try:
-        fh.seek(0)
-        if encoding is not None:
-            up = Unpickler(fh, encoding=encoding)
-        else:
-            up = Unpickler(fh)
-        # "Unpickler" has no attribute "is_verbose"  [attr-defined]
-        up.is_verbose = is_verbose  # type: ignore[attr-defined]
-
-        return up.load()
-    except (ValueError, TypeError):
-        raise
+    fh.seek(0)
+    if encoding is not None:
+        up = Unpickler(fh, encoding=encoding)
+    else:
+        up = Unpickler(fh)
+    return up.load()
 
 
 def loads(
@@ -257,9 +153,9 @@ def patch_pickle() -> Generator[None, None, None]:
     """
     Temporarily patch pickle to use our unpickler.
     """
-    orig_loads = pkl.loads
+    orig_loads = pickle.loads
     try:
-        setattr(pkl, "loads", loads)
+        setattr(pickle, "loads", loads)
         yield
     finally:
-        setattr(pkl, "loads", orig_loads)
+        setattr(pickle, "loads", orig_loads)
diff --git a/pandas/core/arrays/sparse/array.py b/pandas/core/arrays/sparse/array.py
index fafeedc01b02b..67be5c7fa0853 100644
--- a/pandas/core/arrays/sparse/array.py
+++ b/pandas/core/arrays/sparse/array.py
@@ -1375,23 +1375,6 @@ def _where(self, mask, value):
         result = type(self)._from_sequence(naive_implementation, dtype=dtype)
         return result
 
-    # ------------------------------------------------------------------------
-    # IO
-    # ------------------------------------------------------------------------
-    def __setstate__(self, state) -> None:
-        """Necessary for making this object picklable"""
-        if isinstance(state, tuple):
-            # Compat for pandas < 0.24.0
-            nd_state, (fill_value, sp_index) = state
-            sparse_values = np.array([])
-            sparse_values.__setstate__(nd_state)
-
-            self._sparse_values = sparse_values
-            self._sparse_index = sp_index
-            self._dtype = SparseDtype(sparse_values.dtype, fill_value)
-        else:
-            self.__dict__.update(state)
-
     def nonzero(self) -> tuple[npt.NDArray[np.int32]]:
         if self.fill_value == 0:
             return (self.sp_index.indices,)
diff --git a/pandas/core/internals/managers.py b/pandas/core/internals/managers.py
index c6a8b61e0c51e..60285f987cce1 100644
--- a/pandas/core/internals/managers.py
+++ b/pandas/core/internals/managers.py
@@ -1930,11 +1930,6 @@ def unpickle_block(values, mgr_locs, ndim: int) -> Block:
         else:
             raise NotImplementedError("pre-0.14.1 pickles are no longer supported")
 
-        self._post_setstate()
-
-    def _post_setstate(self) -> None:
-        pass
-
     @cache_readonly
     def _block(self) -> Block:
         return self.blocks[0]
diff --git a/pandas/io/pickle.py b/pandas/io/pickle.py
index 89867ab4f19d0..54facd89dc5d9 100644
--- a/pandas/io/pickle.py
+++ b/pandas/io/pickle.py
@@ -156,7 +156,7 @@ def read_pickle(
 
     Notes
     -----
-    read_pickle is only guaranteed to be backwards compatible to pandas 0.20.3
+    read_pickle is only guaranteed to be backwards compatible to pandas 1.0.0
     provided the object was serialized with to_pickle.
 
     Examples
diff --git a/pandas/tests/io/data/legacy_hdf/periodindex_0.20.1_x86_64_darwin_2.7.13.h5 b/pandas/tests/io/data/legacy_hdf/periodindex_0.20.1_x86_64_darwin_2.7.13.h5
deleted file mode 100644
index 6fb92d3c564bd..0000000000000
Binary files a/pandas/tests/io/data/legacy_hdf/periodindex_0.20.1_x86_64_darwin_2.7.13.h5 and /dev/null differ
diff --git a/pandas/tests/io/data/pickle/categorical.0.25.0.pickle b/pandas/tests/io/data/pickle/categorical.0.25.0.pickle
deleted file mode 100644
index b756060c83d94..0000000000000
Binary files a/pandas/tests/io/data/pickle/categorical.0.25.0.pickle and /dev/null differ
diff --git a/pandas/tests/io/data/pickle/test_mi_py27.pkl b/pandas/tests/io/data/pickle/test_mi_py27.pkl
deleted file mode 100644
index 89021dd828108..0000000000000
Binary files a/pandas/tests/io/data/pickle/test_mi_py27.pkl and /dev/null differ
diff --git a/pandas/tests/io/data/pickle/test_py27.pkl b/pandas/tests/io/data/pickle/test_py27.pkl
deleted file mode 100644
index 5308b864bc0c7..0000000000000
Binary files a/pandas/tests/io/data/pickle/test_py27.pkl and /dev/null differ
diff --git a/pandas/tests/io/pytables/test_read.py b/pandas/tests/io/pytables/test_read.py
index c8563ee4af4a8..0fd0a8774bbf4 100644
--- a/pandas/tests/io/pytables/test_read.py
+++ b/pandas/tests/io/pytables/test_read.py
@@ -348,34 +348,6 @@ def test_read_hdf_series_mode_r(tmp_path, format, setup_path):
     tm.assert_series_equal(result, series)
 
 
-@pytest.mark.filterwarnings(r"ignore:Period with BDay freq is deprecated:FutureWarning")
-@pytest.mark.filterwarnings(r"ignore:PeriodDtype\[B\] is deprecated:FutureWarning")
-def test_read_py2_hdf_file_in_py3(datapath):
-    # GH 16781
-
-    # tests reading a PeriodIndex DataFrame written in Python2 in Python3
-
-    # the file was generated in Python 2.7 like so:
-    #
-    # df = DataFrame([1.,2,3], index=pd.PeriodIndex(
-    #              ['2015-01-01', '2015-01-02', '2015-01-05'], freq='B'))
-    # df.to_hdf('periodindex_0.20.1_x86_64_darwin_2.7.13.h5', 'p')
-
-    expected = DataFrame(
-        [1.0, 2, 3],
-        index=pd.PeriodIndex(["2015-01-01", "2015-01-02", "2015-01-05"], freq="B"),
-    )
-
-    with ensure_clean_store(
-        datapath(
-            "io", "data", "legacy_hdf", "periodindex_0.20.1_x86_64_darwin_2.7.13.h5"
-        ),
-        mode="r",
-    ) as store:
-        result = store["p"]
-    tm.assert_frame_equal(result, expected)
-
-
 def test_read_infer_string(tmp_path, setup_path):
     # GH#54431
     pytest.importorskip("pyarrow")
diff --git a/pandas/tests/io/test_common.py b/pandas/tests/io/test_common.py
index b43f430b8895b..41800dc4d7256 100644
--- a/pandas/tests/io/test_common.py
+++ b/pandas/tests/io/test_common.py
@@ -297,7 +297,13 @@ def test_read_expands_user_home_dir(
             (
                 pd.read_pickle,
                 "os",
-                ("io", "data", "pickle", "categorical.0.25.0.pickle"),
+                (
+                    "io",
+                    "data",
+                    "legacy_pickle",
+                    "1.4.2",
+                    "1.4.2_x86_64_linux_3.9.7.pickle",
+                ),
             ),
         ],
     )
@@ -310,10 +316,9 @@ def test_read_fspath_all(self, reader, module, path, datapath):
         expected = reader(path)
 
         if path.endswith(".pickle"):
-            # categorical
-            tm.assert_categorical_equal(result, expected)
-        else:
-            tm.assert_frame_equal(result, expected)
+            result = result["frame"]["float"]
+            expected = expected["frame"]["float"]
+        tm.assert_frame_equal(result, expected)
 
     @pytest.mark.parametrize(
         "writer_name, writer_kwargs, module",
diff --git a/pandas/tests/io/test_pickle.py b/pandas/tests/io/test_pickle.py
index 57c7829924531..5b8fddebd4ffa 100644
--- a/pandas/tests/io/test_pickle.py
+++ b/pandas/tests/io/test_pickle.py
@@ -399,31 +399,6 @@ def test_read(self, protocol, get_random_path):
             tm.assert_frame_equal(df, df2)
 
 
-@pytest.mark.parametrize(
-    ["pickle_file", "excols"],
-    [
-        ("test_py27.pkl", Index(["a", "b", "c"])),
-        (
-            "test_mi_py27.pkl",
-            pd.MultiIndex.from_arrays([["a", "b", "c"], ["A", "B", "C"]]),
-        ),
-    ],
-)
-def test_unicode_decode_error(datapath, pickle_file, excols):
-    # pickle file written with py27, should be readable without raising
-    #  UnicodeDecodeError, see GH#28645 and GH#31988
-    path = datapath("io", "data", "pickle", pickle_file)
-    df = pd.read_pickle(path)
-
-    # just test the columns are correct since the values are random
-    tm.assert_index_equal(df.columns, excols)
-
-
-# ---------------------
-# tests for buffer I/O
-# ---------------------
-
-
 def test_pickle_buffer_roundtrip():
     with tm.ensure_clean() as path:
         df = DataFrame(