diff --git a/sphinx/ext/autosummary/__init__.py b/sphinx/ext/autosummary/__init__.py
index c3bd7dd4b0..6bba9bd0ff 100644
--- a/sphinx/ext/autosummary/__init__.py
+++ b/sphinx/ext/autosummary/__init__.py
@@ -58,6 +58,7 @@ from inspect import Parameter
 from types import ModuleType
 from typing import TYPE_CHECKING, cast
 
+import docutils
 from docutils import nodes
 from docutils.parsers.rst import directives
 from docutils.parsers.rst.states import RSTStateMachine, state_classes
@@ -398,8 +399,9 @@ class Autosummary(SphinxDirective):
         table.append(real_table)
         group = nodes.tgroup('', cols=2)
         real_table.append(group)
-        group.append(nodes.colspec('', colwidth=10))
-        group.append(nodes.colspec('', colwidth=90))
+        for width in (10, 90):
+            colwidth = str(width) if docutils.__version_info__[:2] >= (1, 0) else width
+            group.append(nodes.colspec('', colwidth=colwidth))
         body = nodes.tbody('')
         group.append(body)
 
diff --git a/sphinx/ext/doctest.py b/sphinx/ext/doctest.py
index 9da6c4318d..308c186f31 100644
--- a/sphinx/ext/doctest.py
+++ b/sphinx/ext/doctest.py
@@ -24,6 +24,7 @@ from sphinx.builders import Builder
 from sphinx.locale import __
 from sphinx.util import logging
 from sphinx.util.docutils import SphinxDirective
+from sphinx.util.nodes import _is_doctest_block
 from sphinx.util.osutil import relpath
 
 if TYPE_CHECKING:
@@ -661,4 +662,4 @@ def _condition_default(node: Node) -> bool:
 
 
 def _condition_with_doctest(node: Node) -> bool:
-    return _condition_default(node) or isinstance(node, nodes.doctest_block)
+    return _condition_default(node) or _is_doctest_block(node)
diff --git a/sphinx/io.py b/sphinx/io.py
index 8ac92f48e2..149083c501 100644
--- a/sphinx/io.py
+++ b/sphinx/io.py
@@ -5,9 +5,10 @@ from __future__ import annotations
 import warnings
 from typing import TYPE_CHECKING
 
+import docutils
 from docutils.io import FileInput
 from docutils.readers import standalone
-from docutils.transforms.references import DanglingReferences
+from docutils.transforms import references
 from docutils.writers import UnfilteredWriter
 
 from sphinx.deprecation import RemovedInSphinx10Warning
@@ -52,7 +53,9 @@ class SphinxBaseReader(standalone.Reader):  # type: ignore[type-arg]
         transforms = super().get_transforms() + self.transforms
 
         # remove transforms which is not needed for Sphinx
-        unused = [DanglingReferences]
+        unused: list[type[Transform]] = [references.DanglingReferences]
+        if docutils.__version_info__[:2] >= (1, 0):
+            unused.append(references.ReportUnreferencedTargets)  # type: ignore[attr-defined]
         for transform in unused:
             if transform in transforms:
                 transforms.remove(transform)
diff --git a/sphinx/transforms/__init__.py b/sphinx/transforms/__init__.py
index eb04025954..c7c4e80572 100644
--- a/sphinx/transforms/__init__.py
+++ b/sphinx/transforms/__init__.py
@@ -6,6 +6,7 @@ import re
 import unicodedata
 from typing import TYPE_CHECKING, cast
 
+import docutils
 from docutils import nodes
 from docutils.transforms import Transform, Transformer
 from docutils.transforms.parts import ContentsFilter
@@ -19,7 +20,11 @@ from sphinx.deprecation import _deprecation_warning
 from sphinx.locale import _, __
 from sphinx.util import logging
 from sphinx.util.i18n import format_date
-from sphinx.util.nodes import apply_source_workaround, is_smartquotable
+from sphinx.util.nodes import (
+    _is_doctest_block,
+    apply_source_workaround,
+    is_smartquotable,
+)
 
 if TYPE_CHECKING:
     from collections.abc import Iterable, Iterator
@@ -183,7 +188,7 @@ class HandleCodeBlocks(SphinxTransform):
     def apply(self, **kwargs: Any) -> None:
         # move doctest blocks out of blockquotes
         for node in self.document.findall(nodes.block_quote):
-            if all(isinstance(child, nodes.doctest_block) for child in node.children):
+            if all(_is_doctest_block(child) for child in node.children):
                 node.replace_self(node.children)
         # combine successive doctest blocks
         # for node in self.document.findall(nodes.doctest_block):
@@ -278,6 +283,8 @@ class ExtraTranslatableNodes(SphinxTransform):
             return
 
         def is_translatable_node(node: Node) -> TypeIs[nodes.Element]:
+            if _is_doctest_block(node):
+                return 'doctest-block' in targets
             return isinstance(node, target_nodes)
 
         for node in self.document.findall(is_translatable_node):
@@ -325,13 +332,18 @@ class UnreferencedFootnotesDetector(SphinxTransform):
 
 
 class DoctestTransform(SphinxTransform):
-    """Set "doctest" style to each doctest_block node"""
+    """Set the style and highlighting language of doctest blocks."""
 
     default_priority = 500
 
     def apply(self, **kwargs: Any) -> None:
         for node in self.document.findall(nodes.doctest_block):
             node['classes'].append('doctest')
+        if docutils.__version_info__[:2] >= (1, 0):
+            # Docutils 1.0 represents doctests as literal blocks.
+            for literal in self.document.findall(nodes.literal_block):
+                if _is_doctest_block(literal):
+                    literal.setdefault('language', 'pycon')
 
 
 class FilterSystemMessages(SphinxTransform):
diff --git a/sphinx/transforms/references.py b/sphinx/transforms/references.py
index 8655dbfa5f..c8c2915fba 100644
--- a/sphinx/transforms/references.py
+++ b/sphinx/transforms/references.py
@@ -4,6 +4,7 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
+import docutils
 from docutils.transforms.references import DanglingReferences
 
 from sphinx.transforms import SphinxTransform
@@ -42,7 +43,10 @@ class SphinxDomains(SphinxTransform):
 
 
 def setup(app: Sphinx) -> ExtensionMetadata:
-    app.add_transform(SphinxDanglingReferences)
+    # Docutils 1.0 splits reference matching and reporting into separate
+    # transforms, which are already provided by the standalone reader.
+    if docutils.__version_info__[:2] < (1, 0):
+        app.add_transform(SphinxDanglingReferences)
     app.add_transform(SphinxDomains)
 
     return {
diff --git a/sphinx/util/docutils.py b/sphinx/util/docutils.py
index 74a53ef605..a992e925e0 100644
--- a/sphinx/util/docutils.py
+++ b/sphinx/util/docutils.py
@@ -18,7 +18,7 @@ from docutils.io import FileOutput
 from docutils.parsers.rst import Directive, directives, roles
 from docutils.readers import standalone
 from docutils.statemachine import StateMachine
-from docutils.transforms.references import DanglingReferences
+from docutils.transforms import references
 from docutils.utils import Reporter, unescape
 
 from sphinx.errors import SphinxError
@@ -77,11 +77,18 @@ if TYPE_CHECKING:
         ) -> tuple[RoleFunction | None, list[system_message]]: ...
 
 
-_READER_TRANSFORMS = [
-    transform
-    for transform in standalone.Reader().get_transforms()
-    if transform is not DanglingReferences
-]
+if docutils.__version_info__[:2] >= (1, 0):
+    _READER_TRANSFORMS = [
+        transform
+        for transform in standalone.Reader().get_transforms()
+        if transform is not references.ReportUnreferencedTargets  # type: ignore[attr-defined]
+    ]
+else:
+    _READER_TRANSFORMS = [
+        transform
+        for transform in standalone.Reader().get_transforms()
+        if transform is not references.DanglingReferences
+    ]
 
 
 additional_nodes: set[type[Element]] = set()
diff --git a/sphinx/util/nodes.py b/sphinx/util/nodes.py
index 90c44c6a9c..3a1805a2ea 100644
--- a/sphinx/util/nodes.py
+++ b/sphinx/util/nodes.py
@@ -8,6 +8,7 @@ import unicodedata
 from io import StringIO
 from typing import TYPE_CHECKING, Any, cast
 
+import docutils
 from docutils import nodes
 from docutils.nodes import Node
 
@@ -287,6 +288,15 @@ IMAGE_TYPE_NODES = (
 )  # fmt: skip
 
 
+def _is_doctest_block(node: Node) -> bool:
+    if docutils.__version_info__[:2] >= (1, 0) and isinstance(
+        node, nodes.literal_block
+    ):
+        return 'doctest' in node['classes']
+    # Also accept doctest_block nodes from third-party parsers on Docutils 1.0.
+    return isinstance(node, nodes.doctest_block)
+
+
 def _clean_extracted_message(text: str) -> str:
     """Remove trailing backslashes from each line of *text*."""
     if '\\' in text:
diff --git a/sphinx/writers/html5.py b/sphinx/writers/html5.py
index 5ab57784c7..3c6060eaf1 100644
--- a/sphinx/writers/html5.py
+++ b/sphinx/writers/html5.py
@@ -7,6 +7,7 @@ import re
 import urllib.parse
 from typing import TYPE_CHECKING
 
+import docutils
 from docutils import nodes
 from docutils.writers.html5_polyglot import HTMLTranslator as BaseTranslator
 
@@ -672,6 +673,15 @@ class HTML5Translator(SphinxTranslator, BaseTranslator):
     def depart_block_quote(self, node: Element) -> None:
         self.body.append('</div></blockquote>\n')
 
+    if docutils.__version_info__[:2] >= (1, 0):
+
+        def visit_attribution(self, node: Element) -> None:
+            # Keep attributions inside our blockquote wrapper. Docutils 1.0's
+            # visitor closes the blockquote before emitting the attribution.
+            prefix, suffix = self.attribution_formats[self.settings.attribution]
+            self.context.append(suffix)
+            self.body.append(self.starttag(node, 'p', prefix, CLASS='attribution'))
+
     # overwritten
     def visit_literal(self, node: Element) -> None:
         if 'kbd' in node['classes']:
diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index b6dc333cb3..141eb8eae7 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -11,6 +11,7 @@ from collections import defaultdict
 from pathlib import Path
 from typing import TYPE_CHECKING, cast
 
+import docutils
 from docutils import nodes, writers
 from roman_numerals import RomanNumeral
 
@@ -1249,7 +1250,12 @@ class LaTeXTranslator(SphinxTranslator):
         assert self.table is not None
         self.table.colcount += 1
         if 'colwidth' in node:
-            self.table.colwidths.append(node['colwidth'])
+            if docutils.__version_info__[:2] >= (1, 0):
+                # breaking change in Docutils 1.0
+                # https://sourceforge.net/p/docutils/code/10397
+                self.table.colwidths.append(int(node['colwidth']))
+            else:
+                self.table.colwidths.append(node['colwidth'])
         if 'stub' in node:
             self.table.stubs.append(self.table.colcount - 1)
 
diff --git a/sphinx/writers/texinfo.py b/sphinx/writers/texinfo.py
index a40d65ebc7..e984defa15 100644
--- a/sphinx/writers/texinfo.py
+++ b/sphinx/writers/texinfo.py
@@ -7,6 +7,7 @@ import re
 import textwrap
 from typing import TYPE_CHECKING, cast
 
+import docutils
 from docutils import nodes, writers
 
 from sphinx import __display_version__, addnodes
@@ -1041,7 +1042,12 @@ class TexinfoTranslator(SphinxTranslator):
         pass
 
     def visit_colspec(self, node: Element) -> None:
-        self.colwidths.append(node['colwidth'])
+        if docutils.__version_info__[:2] >= (1, 0):
+            # breaking change in Docutils 1.0
+            # https://sourceforge.net/p/docutils/code/10397
+            self.colwidths.append(int(node['colwidth']))
+        else:
+            self.colwidths.append(node['colwidth'])
         if len(self.colwidths) != self.n_cols:
             return
         self.body.append('\n\n@multitable ')
diff --git a/sphinx/writers/text.py b/sphinx/writers/text.py
index a542ab45c0..f6b3b7ee8f 100644
--- a/sphinx/writers/text.py
+++ b/sphinx/writers/text.py
@@ -9,6 +9,7 @@ import textwrap
 from itertools import chain, groupby, pairwise
 from typing import TYPE_CHECKING, cast
 
+import docutils
 from docutils import nodes, writers
 from docutils.utils import column_width
 
@@ -904,7 +905,12 @@ class TextTranslator(SphinxTranslator):
         raise nodes.SkipNode
 
     def visit_colspec(self, node: Element) -> None:
-        self.table.colwidth.append(node['colwidth'])
+        if docutils.__version_info__[:2] >= (1, 0):
+            # breaking change in Docutils 1.0
+            # https://sourceforge.net/p/docutils/code/10397
+            self.table.colwidth.append(int(node['colwidth']))
+        else:
+            self.table.colwidth.append(node['colwidth'])
         raise nodes.SkipNode
 
     def visit_tgroup(self, node: Element) -> None:
diff --git a/tests/test_builders/test_build_html_5_output.py b/tests/test_builders/test_build_html_5_output.py
index b712d1415a..9ab869153e 100644
--- a/tests/test_builders/test_build_html_5_output.py
+++ b/tests/test_builders/test_build_html_5_output.py
@@ -5,11 +5,17 @@ from __future__ import annotations
 import re
 from typing import TYPE_CHECKING
 
+import docutils
 import pytest
 from docutils import nodes
 
 from tests.test_builders.xpath_util import check_xpath
 
+if docutils.__version_info__[:2] >= (1, 0):
+    _RFC_1_URL = 'https://datatracker.ietf.org/doc/html/rfc1/'
+else:
+    _RFC_1_URL = 'https://datatracker.ietf.org/doc/html/rfc1.html'
+
 if TYPE_CHECKING:
     from collections.abc import Callable, Iterable
     from pathlib import Path
@@ -147,14 +153,12 @@ def tail_check(check: str) -> Callable[[Iterable[Element]], Literal[True]]:
         ),
         (
             'markup.html',
-            ".//a[@href='https://datatracker.ietf.org/doc/html/rfc1.html']"
-            "[@class='rfc reference external']/strong",
+            f".//a[@href='{_RFC_1_URL}'][@class='rfc reference external']/strong",
             'RFC 1',
         ),
         (
             'markup.html',
-            ".//a[@href='https://datatracker.ietf.org/doc/html/rfc1.html']"
-            "[@class='rfc reference external']/strong",
+            f".//a[@href='{_RFC_1_URL}'][@class='rfc reference external']/strong",
             'Request for Comments #1',
         ),
         (
diff --git a/tests/test_markup/test_markup.py b/tests/test_markup/test_markup.py
index 4889ed6daa..cff335ba7e 100644
--- a/tests/test_markup/test_markup.py
+++ b/tests/test_markup/test_markup.py
@@ -5,6 +5,7 @@ from __future__ import annotations
 import re
 from types import SimpleNamespace
 
+import docutils
 import pytest
 from docutils import nodes, utils
 from docutils.parsers.rst import Parser as RstParser
@@ -23,6 +24,11 @@ from sphinx.writers.latex import LaTeXTranslator, LaTeXWriter
 
 from tests.utils import extract_node
 
+if docutils.__version_info__[:2] >= (1, 0):
+    _RFC_2324_URL = 'https://datatracker.ietf.org/doc/html/rfc2324/'
+else:
+    _RFC_2324_URL = 'https://datatracker.ietf.org/doc/html/rfc2324.html'
+
 TYPE_CHECKING = False
 if TYPE_CHECKING:
     from sphinx.environment import BuildEnvironment
@@ -212,12 +218,12 @@ def rst_to_latex(rst: str, *, app: SphinxTestApp) -> str:
             ':rfc:`2324`',
             (
                 '<p><span class="target" id="index-0"></span><a class="rfc reference external" '
-                'href="https://datatracker.ietf.org/doc/html/rfc2324.html"><strong>RFC 2324</strong></a></p>'
+                f'href="{_RFC_2324_URL}"><strong>RFC 2324</strong></a></p>'
             ),
             (
                 '\\sphinxAtStartPar\n'
                 '\\index{RFC@\\spxentry{RFC}!RFC 2324@\\spxentry{RFC 2324}}'
-                '\\sphinxhref{https://datatracker.ietf.org/doc/html/rfc2324.html}'
+                rf'\sphinxhref{{{_RFC_2324_URL}}}'
                 '{\\sphinxstylestrong{RFC 2324}}'
             ),
         ),
@@ -226,13 +232,13 @@ def rst_to_latex(rst: str, *, app: SphinxTestApp) -> str:
             ':rfc:`2324#section-1`',
             (
                 '<p><span class="target" id="index-0"></span><a class="rfc reference external" '
-                'href="https://datatracker.ietf.org/doc/html/rfc2324.html#section-1">'
+                f'href="{_RFC_2324_URL}#section-1">'
                 '<strong>RFC 2324 Section 1</strong></a></p>'
             ),
             (
                 '\\sphinxAtStartPar\n'
                 '\\index{RFC@\\spxentry{RFC}!RFC 2324 Section 1@\\spxentry{RFC 2324 Section 1}}'
-                '\\sphinxhref{https://datatracker.ietf.org/doc/html/rfc2324.html\\#section-1}'
+                rf'\sphinxhref{{{_RFC_2324_URL}\#section-1}}'
                 '{\\sphinxstylestrong{RFC 2324 Section 1}}'
             ),
         ),
@@ -462,6 +468,16 @@ def test_inline(
         assert latex_expected == latex_translated, f'from {rst!r}'
 
 
+@pytest.mark.sphinx('html', testroot='_blank')
+def test_block_quote_attribution(app: SphinxTestApp) -> None:
+    html = rst_to_html('    A quotation.\n\n    -- The author\n', app=app)
+    assert html == (
+        '<blockquote>\n<div><p>A quotation.</p>\n'
+        '<p class="attribution">—The author</p>\n'
+        '</div></blockquote>'
+    )
+
+
 @pytest.mark.parametrize(
     ('rst', 'html_expected', 'latex_expected'),
     [
diff --git a/tests/test_transforms/test_transforms_doctest.py b/tests/test_transforms/test_transforms_doctest.py
new file mode 100644
index 0000000000..792096a638
--- /dev/null
+++ b/tests/test_transforms/test_transforms_doctest.py
@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import docutils
+import pytest
+from docutils import nodes
+
+from sphinx.testing import restructuredtext
+
+if TYPE_CHECKING:
+    from sphinx.testing.util import SphinxTestApp
+
+
+@pytest.mark.sphinx('dummy', testroot='_blank')
+def test_indented_doctest(app: SphinxTestApp) -> None:
+    doctree = restructuredtext.parse(app, '    >>> 1 + 1\n    2\n')
+
+    assert len(doctree) == 1
+    node = doctree[0]
+    if docutils.__version_info__[:2] >= (1, 0):
+        assert isinstance(node, nodes.literal_block)
+        assert node['language'] == 'pycon'
+    else:
+        assert isinstance(node, nodes.doctest_block)
+    assert node.astext() == '>>> 1 + 1\n2'
+    assert 'doctest' in node['classes']
+
+
+@pytest.mark.parametrize(
+    ('target', 'translate_doctest', 'translate_literal'),
+    [('doctest-block', True, False), ('literal-block', False, True)],
+)
+@pytest.mark.sphinx('dummy', testroot='_blank')
+def test_doctest_translation(
+    app: SphinxTestApp,
+    target: str,
+    translate_doctest: bool,
+    translate_literal: bool,
+) -> None:
+    app.config.gettext_additional_targets = [target]
+    doctree = restructuredtext.parse(
+        app, '>>> 1 + 1\n2\n\n::\n\n    an ordinary literal block\n'
+    )
+
+    doctest, literal = doctree.children
+    assert isinstance(doctest, nodes.Element)
+    assert doctest.get('translatable', False) is translate_doctest
+    assert isinstance(literal, nodes.Element)
+    assert literal.get('translatable', False) is translate_literal