diff --git a/src/uproot/__init__.py b/src/uproot/__init__.py
index 8777b4122..2d2de7786 100644
--- a/src/uproot/__init__.py
+++ b/src/uproot/__init__.py
@@ -72,7 +72,6 @@
 isort:skip_file
 """
 
-
 from uproot.version import __version__
 import uproot.const
 import uproot.extras
@@ -92,6 +91,7 @@
 from uproot.source.xrootd import MultithreadedXRootDSource
 from uproot.source.s3 import S3Source
 from uproot.source.object import ObjectSource
+from uproot.source.fsspec import FSSpecSource
 from uproot.source.cursor import Cursor
 from uproot.source.futures import TrivialExecutor
 from uproot.source.futures import ThreadPoolExecutor
diff --git a/src/uproot/_dask.py b/src/uproot/_dask.py
index b1f033c80..38bb213c7 100644
--- a/src/uproot/_dask.py
+++ b/src/uproot/_dask.py
@@ -142,11 +142,6 @@ def dask(
     Options (type; default):
 
     * handler (:doc:`uproot.source.chunk.Source` class; None)
-    * file_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * xrootd_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * s3_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * http_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * object_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
     * timeout (float for HTTP, int for XRootD; 30)
     * max_num_elements (None or int; None)
     * num_workers (int; 1)
diff --git a/src/uproot/_util.py b/src/uproot/_util.py
index 25c34d0bb..28ac3665e 100644
--- a/src/uproot/_util.py
+++ b/src/uproot/_util.py
@@ -369,63 +369,30 @@ def file_path_to_source_class(file_path, options):
     Use a file path to get the :doc:`uproot.source.chunk.Source` class that would read it.
 
     Returns a tuple of (class, file_path) where the class is a subclass of :doc:`uproot.source.chunk.Source`.
-
-    The "handler" option is the preferred way to specify a custom source class.
-    The "*_handler" options are for backwards compatibility and will override the "handler" option if set.
     """
+
     import uproot.source.chunk
 
     file_path = regularize_path(file_path)
 
-    out = options["handler"]
-    if out is not None:
-        if not (isinstance(out, type) and issubclass(out, uproot.source.chunk.Source)):
-            raise TypeError(
-                f"'handler' is not a class object inheriting from Source: {out!r}"
-            )
-        # check if "object_handler" is set
-        if (
-            options["object_handler"] is not None
-            or options["file_handler"] is not None
-            or options["xrootd_handler"] is not None
-            or options["s3_handler"] is not None
-            or options["http_handler"] is not None
+    source_cls = options["handler"]
+    if source_cls is not None:
+        if not (
+            isinstance(source_cls, type)
+            and issubclass(source_cls, uproot.source.chunk.Source)
         ):
-            # These options will override the "handler" option for backwards compatibility
-            warnings.warn(
-                """In version 5.2.0, the '*_handler' argument ('http_handler`, 's3_handler', etc.) will be removed from 'uproot.open'. Use 'handler' instead.""",
-                stacklevel=1,
+            raise TypeError(
+                f"'handler' is not a class object inheriting from Source: {source_cls!r}"
             )
-        else:
-            return out, file_path
+        return source_cls, file_path
 
     if (
         not isinstance(file_path, str)
         and hasattr(file_path, "read")
         and hasattr(file_path, "seek")
     ):
-        out = options["object_handler"]
-        if out is None:
-            out = uproot.source.object.ObjectSource
-        else:
-            warnings.warn(
-                f"""In version 5.2.0, the 'object_handler' argument will be removed from 'uproot.open'. Use
-uproot.open(..., handler={out!r})
-instead.
-
-To raise these warnings as errors (and get stack traces to find out where they're called), run
-import warnings
-warnings.filterwarnings("error", module="uproot.*")
-after the first `import uproot` or use `@pytest.mark.filterwarnings("error:::uproot.*")` in pytest.""",
-                DeprecationWarning,
-                stacklevel=1,
-            )
-        if not (isinstance(out, type) and issubclass(out, uproot.source.chunk.Source)):
-            raise TypeError(
-                f"'object_handler' is not a class object inheriting from Source: {out!r}"
-            )
-
-        return out, file_path
+        source_cls = uproot.source.object.ObjectSource
+        return source_cls, file_path
 
     windows_absolute_path = None
     if win and _windows_absolute_path_pattern.match(file_path) is not None:
@@ -457,107 +424,27 @@ def file_path_to_source_class(file_path, options):
         else:
             file_path = windows_absolute_path
 
-        out = options["file_handler"]
-        if out is None:
-            out = uproot.source.file.MemmapSource
-        else:
-            warnings.warn(
-                f"""In version 5.2.0, the 'file_handler' argument will be removed from 'uproot.open'. Use
-    uproot.open(..., handler={out!r}
-    instead.
-
-    To raise these warnings as errors (and get stack traces to find out where they're called), run
-    import warnings
-    warnings.filterwarnings("error", module="uproot.*")
-    after the first `import uproot` or use `@pytest.mark.filterwarnings("error:::uproot.*")` in pytest.""",
-                DeprecationWarning,
-                stacklevel=1,
-            )
+        # uproot.source.file.MemmapSource
+        source_cls = uproot.source.fsspec.FSSpecSource
 
-        if not (isinstance(out, type) and issubclass(out, uproot.source.chunk.Source)):
-            raise TypeError(
-                "'file_handler' is not a class object inheriting from Source: "
-                + repr(out)
-            )
-        return out, os.path.expanduser(file_path)
+        return source_cls, os.path.expanduser(file_path)
 
     elif scheme == "root":
-        out = options["xrootd_handler"]
-        if out is None:
-            out = uproot.source.xrootd.XRootDSource
-        else:
-            warnings.warn(
-                f"""In version 5.2.0, the 'xrootd_handler' argument will be removed from 'uproot.open'. Use
-    uproot.open(..., handler={out!r}
-    instead.
-
-    To raise these warnings as errors (and get stack traces to find out where they're called), run
-    import warnings
-    warnings.filterwarnings("error", module="uproot.*")
-    after the first `import uproot` or use `@pytest.mark.filterwarnings("error:::uproot.*")` in pytest.""",
-                DeprecationWarning,
-                stacklevel=1,
-            )
-        if not (isinstance(out, type) and issubclass(out, uproot.source.chunk.Source)):
-            raise TypeError(
-                "'xrootd_handler' is not a class object inheriting from Source: "
-                + repr(out)
-            )
-        return out, file_path
+        # uproot.source.xrootd.XRootDSource
+        source_cls = uproot.source.fsspec.FSSpecSource
+        return source_cls, file_path
 
     elif scheme == "s3":
-        out = options["s3_handler"]
-        if out is None:
-            out = uproot.source.s3.S3Source
-        else:
-            warnings.warn(
-                f"""In version 5.2.0, the 's3_handler' argument will be removed from 'uproot.open'. Use
-uproot.open(..., handler={out!r}
-instead.
-
-To raise these warnings as errors (and get stack traces to find out where they're called), run
-import warnings
-warnings.filterwarnings("error", module="uproot.*")
-after the first `import uproot` or use `@pytest.mark.filterwarnings("error:::uproot.*")` in pytest.""",
-                DeprecationWarning,
-                stacklevel=1,
-            )
-        if not (isinstance(out, type) and issubclass(out, uproot.source.chunk.Source)):
-            raise TypeError(
-                "'s3' is not a class object inheriting from Source: " + repr(out)
-            )
-        return out, file_path
+        # https://github.com/scikit-hep/uproot5/pull/1012
+        source_cls = uproot.source.s3.S3Source
+        return source_cls, file_path
 
     elif scheme in ("http", "https"):
-        out = options["http_handler"]
-        if out is None:
-            out = uproot.source.http.HTTPSource
-        else:
-            warnings.warn(
-                f"""In version 5.2.0, the 'http_handler' argument will be removed from 'uproot.open'. Use
-uproot.open(..., handler={out!r}
-instead.
-
-To raise these warnings as errors (and get stack traces to find out where they're called), run
-import warnings
-warnings.filterwarnings("error", module="uproot.*")
-after the first `import uproot` or use `@pytest.mark.filterwarnings("error:::uproot.*")` in pytest.""",
-                DeprecationWarning,
-                stacklevel=1,
-            )
-        if not (isinstance(out, type) and issubclass(out, uproot.source.chunk.Source)):
-            raise TypeError(
-                "'http_handler' is not a class object inheriting from Source: "
-                + repr(out)
-            )
-        return out, file_path
-
-    else:
-        # try to use fsspec before raising an error
-        if scheme in _schemes:
-            return uproot.source.fsspec.FSSpecSource, file_path
+        # uproot.source.http.HTTPSource
+        source_cls = uproot.source.fsspec.FSSpecSource
+        return source_cls, file_path
 
-        raise ValueError(f"URI scheme not recognized: {file_path}")
+    return uproot.source.fsspec.FSSpecSource, file_path
 
 
 if isinstance(__builtins__, dict):
diff --git a/src/uproot/behaviors/TBranch.py b/src/uproot/behaviors/TBranch.py
index 7fb3e3c45..a82603176 100644
--- a/src/uproot/behaviors/TBranch.py
+++ b/src/uproot/behaviors/TBranch.py
@@ -154,11 +154,6 @@ def iterate(
     Options (type; default):
 
     * handler (:doc:`uproot.source.chunk.Source` class; None)
-    * file_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * xrootd_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * s3_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * http_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * object_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
     * timeout (float for HTTP, int for XRootD; 30)
     * max_num_elements (None or int; None)
     * num_workers (int; 1)
@@ -328,11 +323,6 @@ def concatenate(
     Options (type; default):
 
     * handler (:doc:`uproot.source.chunk.Source` class; None)
-    * file_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * xrootd_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * s3_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * http_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * object_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
     * timeout (float for HTTP, int for XRootD; 30)
     * max_num_elements (None or int; None)
     * num_workers (int; 1)
diff --git a/src/uproot/reading.py b/src/uproot/reading.py
index 63aa88e6f..935c6e646 100644
--- a/src/uproot/reading.py
+++ b/src/uproot/reading.py
@@ -12,11 +12,11 @@
 import struct
 import sys
 import uuid
-import warnings
 from collections.abc import Mapping, MutableMapping
 
 import uproot
 import uproot.behaviors.TBranch
+import uproot.source.fsspec
 from uproot._util import no_filter
 
 
@@ -43,7 +43,7 @@ def open(
             ``"rel/file.root:tdirectory/ttree"``, ``Path("rel:/file.root")``,
             ``Path("/abs/path:stuff.root")``
         object_cache (None, MutableMapping, or int): Cache of objects drawn
-            from ROOT directories (e.g histograms, TTrees, other directories);
+            from ROOT directories (e.g. histograms, TTrees, other directories);
             if None, do not use a cache; if an int, create a new cache of this
             size.
         array_cache (None, MutableMapping, or memory size): Cache of arrays
@@ -78,11 +78,6 @@ def open(
     Options (type; default):
 
     * handler (:doc:`uproot.source.chunk.Source` class; None)
-    * file_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * xrootd_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * s3_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * http_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * object_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
     * timeout (float for HTTP, int for XRootD; 30)
     * max_num_elements (None or int; None)
     * num_workers (int; 1)
@@ -157,43 +152,22 @@ def open(
         return file.root_directory[object_path]
 
 
+open.defaults = {
+    "handler": None,
+    "timeout": 30,
+    "max_num_elements": None,
+    "num_workers": 1,
+    "use_threads": sys.platform != "emscripten",
+    "num_fallback_workers": 10,
+    "begin_chunk_size": 403,  # the smallest a ROOT file can be
+    "minimal_ttree_metadata": True,
+}
+
+
 class _OpenDefaults(dict):
-    def __getitem__(self, where):
-        if where == "xrootd_handler" and where not in self:
-            # See https://github.com/scikit-hep/uproot5/issues/294
-            if uproot.extras.older_xrootd("5.2.0"):
-                message = (
-                    f"XRootD {uproot.extras.xrootd_version()} is not fully supported; "
-                    """either upgrade to 5.2.0+ or set
-
-    open.defaults["xrootd_handler"] = uproot.MultithreadedXRootDSource
-"""
-                )
-                warnings.warn(message, FutureWarning, stacklevel=1)
-
-            # The key should still be set, regardless of whether we see the warning.
-            self["xrootd_handler"] = uproot.source.xrootd.XRootDSource
-
-        return dict.__getitem__(self, where)
-
-
-open.defaults = _OpenDefaults(
-    {
-        "handler": None,  # To be updated to fsspec source
-        "file_handler": None,  # Deprecated
-        "s3_handler": None,  # Deprecated
-        "http_handler": None,  # Deprecated
-        "object_handler": None,  # Deprecated
-        "xrootd_handler": None,  # Deprecated
-        "timeout": 30,
-        "max_num_elements": None,
-        "num_workers": 1,
-        "use_threads": sys.platform != "emscripten",
-        "num_fallback_workers": 10,
-        "begin_chunk_size": 403,  # the smallest a ROOT file can be
-        "minimal_ttree_metadata": True,
-    }
-)
+    def __init__(self):
+        raise NotImplementedError  # kept for backwards compatibility
+
 
 must_be_attached = [
     "TROOT",
@@ -537,11 +511,6 @@ class ReadOnlyFile(CommonFileMethods):
     Options (type; default):
 
     * handler (:doc:`uproot.source.chunk.Source` class; None)
-    * file_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * xrootd_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * s3_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * http_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
-    * object_handler (:doc:`uproot.source.chunk.Source` class; None) (Deprecated: Use `handler` instead. If set, this will take precedence over `handler`)
     * timeout (float for HTTP, int for XRootD; 30)
     * max_num_elements (None or int; None)
     * num_workers (int; 1)
@@ -572,7 +541,7 @@ def __init__(
         self.decompression_executor = decompression_executor
         self.interpretation_executor = interpretation_executor
 
-        self._options = _OpenDefaults(open.defaults)
+        self._options = open.defaults.copy()
         self._options.update(options)
         for option in ["begin_chunk_size"]:
             self._options[option] = uproot._util.memory_size(self._options[option])
@@ -582,10 +551,10 @@ def __init__(
 
         self.hook_before_create_source()
 
-        Source, file_path = uproot._util.file_path_to_source_class(
+        source_cls, file_path = uproot._util.file_path_to_source_class(
             file_path, self._options
         )
-        self._source = Source(file_path, **self._options)
+        self._source = source_cls(file_path, **self._options)
 
         self.hook_before_get_chunks()
 
diff --git a/tests/test_0017_multi_basket_multi_branch_fetch.py b/tests/test_0017_multi_basket_multi_branch_fetch.py
index b42f6db4b..1ed316f21 100644
--- a/tests/test_0017_multi_basket_multi_branch_fetch.py
+++ b/tests/test_0017_multi_basket_multi_branch_fetch.py
@@ -310,6 +310,7 @@ def test_cache():
         skhep_testdata.data_path("uproot-sample-6.20.04-uncompressed.root"),
         object_cache=100,
         array_cache="100 MB",
+        handler=uproot.source.file.MemmapSource,
     ) as f:
         assert f.cache_key == "db4be408-93ad-11ea-9027-d201a8c0beef:/"
         assert f["sample"].cache_key == "db4be408-93ad-11ea-9027-d201a8c0beef:/sample;1"
diff --git a/tests/test_0066_fix_http_fallback_freeze.py b/tests/test_0066_fix_http_fallback_freeze.py
index 632af99bf..4b6ff26e2 100644
--- a/tests/test_0066_fix_http_fallback_freeze.py
+++ b/tests/test_0066_fix_http_fallback_freeze.py
@@ -1,6 +1,5 @@
 # BSD 3-Clause License; see https://github.com/scikit-hep/uproot5/blob/main/LICENSE
 
-import numpy
 import pytest
 
 import uproot
@@ -8,6 +7,7 @@
 
 @pytest.mark.network
 def test():
+    pytest.importorskip("aiohttp")
     with uproot.open(
         {"http://scikit-hep.org/uproot3/examples/HZZ.root": "events"}
     ) as t:
diff --git a/tests/test_0088_read_with_http.py b/tests/test_0088_read_with_http.py
index 7ba760429..446200595 100644
--- a/tests/test_0088_read_with_http.py
+++ b/tests/test_0088_read_with_http.py
@@ -9,6 +9,8 @@
 
 @pytest.mark.network
 def test_issue176():
+    pytest.importorskip("aiohttp")
+
     with uproot.open(
         "https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root"
     ) as f:
@@ -18,6 +20,8 @@ def test_issue176():
 
 @pytest.mark.network
 def test_issue176_again():
+    pytest.importorskip("aiohttp")
+
     with uproot.open(
         "https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/dalitzdata.root"
     ) as f:
diff --git a/tests/test_0099_read_from_file_object.py b/tests/test_0099_read_from_file_object.py
index f7a9faf02..730b2560b 100644
--- a/tests/test_0099_read_from_file_object.py
+++ b/tests/test_0099_read_from_file_object.py
@@ -4,11 +4,19 @@
 import skhep_testdata
 
 import uproot
+import uproot.source.fsspec
+import uproot.source.object
 
 
-def test():
+@pytest.mark.parametrize(
+    "handler",
+    [None, uproot.source.object.ObjectSource],
+)
+def test_read_from_file_like_object(handler):
     with open(skhep_testdata.data_path("uproot-Zmumu.root"), "rb") as f:
-        assert uproot.open({f: "events"})["px1"].array(library="np")[:10].tolist() == [
+        assert uproot.open({f: "events"}, handler=handler)["px1"].array(library="np")[
+            :10
+        ].tolist() == [
             -41.1952876442,
             35.1180497674,
             35.1180497674,
diff --git a/tests/test_0173_empty_and_multiprocessing_bugs.py b/tests/test_0173_empty_and_multiprocessing_bugs.py
index 8280cadf4..dd5a0efaf 100644
--- a/tests/test_0173_empty_and_multiprocessing_bugs.py
+++ b/tests/test_0173_empty_and_multiprocessing_bugs.py
@@ -1,7 +1,6 @@
 # BSD 3-Clause License; see https://github.com/scikit-hep/uproot5/blob/main/LICENSE
 
 import multiprocessing
-import sys
 
 import pytest
 import skhep_testdata
@@ -17,8 +16,8 @@ def test_empty():
         assert t["z"].array(library="np").tolist() == []
 
 
-def readone(filename):
-    with uproot.open(filename) as f:
+def read_one(filename):
+    with uproot.open(filename, handler=uproot.source.file.MemmapSource) as f:
         f.decompression_executor = uproot.ThreadPoolExecutor()
         t = f["events"]
         b = t["px1"]
@@ -28,7 +27,7 @@ def readone(filename):
 def test_multiprocessing():
     with multiprocessing.Pool(1) as pool:
         out = pool.map(
-            readone,
+            read_one,
             [
                 skhep_testdata.data_path("uproot-Zmumu.root"),
                 skhep_testdata.data_path("uproot-Zmumu-zlib.root"),
diff --git a/tests/test_0220_contiguous_byte_ranges_in_http.py b/tests/test_0220_contiguous_byte_ranges_in_http.py
index 3db77022d..26205206f 100644
--- a/tests/test_0220_contiguous_byte_ranges_in_http.py
+++ b/tests/test_0220_contiguous_byte_ranges_in_http.py
@@ -1,6 +1,5 @@
 # BSD 3-Clause License; see https://github.com/scikit-hep/uproot5/blob/main/LICENSE
 
-import numpy
 import pytest
 
 import uproot
@@ -8,6 +7,8 @@
 
 @pytest.mark.network
 def test():
+    pytest.importorskip("aiohttp")
+
     with uproot.open(
         "https://starterkit.web.cern.ch/starterkit/data/advanced-python-2019/RD_distribution.root:tree"
     ) as f:
diff --git a/tests/test_0302_pickle.py b/tests/test_0302_pickle.py
index fbd436511..c33fb40f6 100644
--- a/tests/test_0302_pickle.py
+++ b/tests/test_0302_pickle.py
@@ -12,7 +12,7 @@
     "handler",
     [
         uproot.source.file.MemmapSource,
-        # uproot.source.fsspec.FSSpecSource,
+        uproot.source.fsspec.FSSpecSource,
     ],
 )
 def test_pickle_roundtrip_local(handler):
@@ -41,7 +41,7 @@ def test_pickle_roundtrip_local(handler):
     "handler",
     [
         uproot.source.http.HTTPSource,
-        # uproot.source.fsspec.FSSpecSource,
+        uproot.source.fsspec.FSSpecSource,
     ],
 )
 @pytest.mark.network
@@ -73,7 +73,7 @@ def test_pickle_roundtrip_http(handler):
     "handler",
     [
         uproot.source.xrootd.XRootDSource,
-        # uproot.source.fsspec.FSSpecSource,
+        uproot.source.fsspec.FSSpecSource,
     ],
 )
 @pytest.mark.network
diff --git a/tests/test_0520_dynamic_classes_cant_be_abc_subclasses.py b/tests/test_0520_dynamic_classes_cant_be_abc_subclasses.py
index 0ac90a524..c50407149 100644
--- a/tests/test_0520_dynamic_classes_cant_be_abc_subclasses.py
+++ b/tests/test_0520_dynamic_classes_cant_be_abc_subclasses.py
@@ -3,9 +3,8 @@
 import pickle
 import sys
 
-import numpy as np
+import uproot
 import pytest
-import skhep_testdata
 
 
 @pytest.mark.skipif(