diff --git a/.github/workflows/branch_off.yml b/.github/workflows/branch_off.yml
index 29255ec4ad..24f0019538 100644
--- a/.github/workflows/branch_off.yml
+++ b/.github/workflows/branch_off.yml
@@ -7,7 +7,7 @@ on:
         description: 'URL of the bump version PR'
         value: ${{ jobs.branch-off.outputs.bump_version_pr_url }}
 env:
-  PYTHON_VERSION: "3.10"
+  PYTHON_VERSION: "3.11"
 
 permissions:
   contents: read
diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
index 04492b7cbb..3d6a5bd4c4 100644
--- a/.github/workflows/e2e.yml
+++ b/.github/workflows/e2e.yml
@@ -14,7 +14,7 @@ on:
       - ".github/workflows/e2e.yml"
 
 env:
-  PYTHON_VERSION: "3.10"
+  PYTHON_VERSION: "3.11"
   OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
   HATCH_VERSION: "1.16.5"
 
diff --git a/.github/workflows/license_compliance.yml b/.github/workflows/license_compliance.yml
index f071017ca0..6c84267dd2 100644
--- a/.github/workflows/license_compliance.yml
+++ b/.github/workflows/license_compliance.yml
@@ -10,7 +10,7 @@ on:
   schedule:
     - cron: "0 0 * * *" # every day at midnight
 env:
-  PYTHON_VERSION: "3.10"
+  PYTHON_VERSION: "3.11"
 
 permissions:
   contents: read
@@ -47,9 +47,7 @@ jobs:
           fail: "Copyleft,Other,Error"
           # Exclusions in the vanilla distribution must be explicitly motivated
           # - tqdm is MLP but there are no better alternatives
-          # - typing_extensions>=4.13.0 has a Python Software Foundation License 2.0 but pip-license-checker does not recognize it
-          #   (https://github.com/pilosus/pip-license-checker/issues/143)
-          exclude: "(?i)^(tqdm|typing_extensions).*"
+          exclude: "(?i)^(tqdm).*"
 
       # We keep the license inventory on FOSSA
       - name: Send license report to Fossa
diff --git a/.github/workflows/promote_unstable_docs.yml b/.github/workflows/promote_unstable_docs.yml
index c2b040b19b..72d6ba755b 100644
--- a/.github/workflows/promote_unstable_docs.yml
+++ b/.github/workflows/promote_unstable_docs.yml
@@ -9,7 +9,7 @@ on:
       - "!v1.[0-9]+.[0-9]+"
 
 env:
-  PYTHON_VERSION: "3.10"
+  PYTHON_VERSION: "3.11"
 
 permissions:
   contents: read
diff --git a/.github/workflows/release_notes.yml b/.github/workflows/release_notes.yml
index bdede41695..26a38e7177 100644
--- a/.github/workflows/release_notes.yml
+++ b/.github/workflows/release_notes.yml
@@ -22,7 +22,7 @@ jobs:
   reno:
     runs-on: ubuntu-slim
     env:
-      PYTHON_VERSION: "3.10"
+      PYTHON_VERSION: "3.11"
     steps:
       - name: Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
diff --git a/.github/workflows/slow.yml b/.github/workflows/slow.yml
index a4922e80a3..74878271d5 100644
--- a/.github/workflows/slow.yml
+++ b/.github/workflows/slow.yml
@@ -11,7 +11,7 @@ name: Slow Integration Tests
 
 env:
   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-  PYTHON_VERSION: "3.10"
+  PYTHON_VERSION: "3.11"
   HATCH_VERSION: "1.16.5"
   HAYSTACK_MPS_ENABLED: false
   HAYSTACK_XPU_ENABLED: false
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index cfb2976638..c684c36bb2 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -29,7 +29,7 @@ env:
   OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
   AZURE_OPENAI_API_KEY: ${{ secrets.AZURE_OPENAI_API_KEY }}
   AZURE_OPENAI_ENDPOINT: ${{ secrets.AZURE_OPENAI_ENDPOINT }}
-  PYTHON_VERSION: "3.10"
+  PYTHON_VERSION: "3.11"
   # numpy's stubs require a 3.12+ interpreter, so type checking runs above the floor.
   # See [tool.mypy] in pyproject.toml.
   MYPY_PYTHON_VERSION: "3.12"
diff --git a/AGENTS.md b/AGENTS.md
index 7da20a2e2f..fcd9217215 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -45,7 +45,7 @@ hatch run test:integration
 ### Type checking with mypy
 hatch run test:types
 
-Type checking targets Python 3.12, above the 3.10 floor in `requires-python`, because numpy's stubs use PEP 695 `type` statements that mypy rejects below 3.12. So mypy will not catch code that breaks on 3.10; the unit test matrix runs on 3.10 and covers that.
+Type checking targets Python 3.12, above the 3.11 floor in `requires-python`, because numpy's stubs use PEP 695 `type` statements that mypy rejects below 3.12. So mypy will not catch code that breaks on 3.11; the unit test matrix runs on 3.11 and covers that.
 
 To fix type issues, avoid `type: ignore`, casts, or assertions when possible. If they are necessary, explain why.
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 36a94bf5bd..5eae8dc604 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -188,7 +188,9 @@ This helps maintainers and keeps the project ready for both human and AI contrib
 
 ### Setting up your development environment
 
-*To run Haystack tests locally, ensure your development environment uses Python >=3.10 and <3.14.*
+*To run Haystack tests locally, ensure your development environment uses Python >=3.11 and <3.16.*
+PyTorch does not publish Python 3.15 wheels on PyPI yet, so on 3.15 create the test environment with
+`UV_EXTRA_INDEX_URL=https://download.pytorch.org/whl/cpu UV_INDEX_STRATEGY=unsafe-best-match hatch env create test`.
 
 Haystack makes heavy use of [Hatch](https://hatch.pypa.io/latest/), a Python project manager that we use to set up the
 virtual environments, build the project, and publish packages. As you can imagine, the first step towards becoming a
@@ -288,10 +290,10 @@ To check for static type errors, run:
 hatch run test:types
 ```
 
-Note that type checking targets Python 3.12, even though Haystack supports 3.10 and above. numpy's
+Note that type checking targets Python 3.12, even though Haystack supports 3.11 and above. numpy's
 type stubs use [PEP 695](https://peps.python.org/pep-0695/) `type` statements, which mypy rejects as
 a syntax error below 3.12. Support for the older versions is covered by the unit test matrix, which
-runs on Python 3.10.
+runs on Python 3.11.
 
 To format your code and perform linting using Ruff (with automatic fixes), run:
 ```sh
diff --git a/haystack/components/converters/image/image_utils.py b/haystack/components/converters/image/image_utils.py
index 0242b0202d..80102bf2be 100644
--- a/haystack/components/converters/image/image_utils.py
+++ b/haystack/components/converters/image/image_utils.py
@@ -7,9 +7,7 @@
 from collections import defaultdict
 from io import BytesIO
 from pathlib import Path
-from typing import TypedDict, Union
-
-from typing_extensions import NotRequired
+from typing import NotRequired, TypedDict, Union
 
 from haystack import logging
 from haystack.dataclasses import ByteStream, Document
diff --git a/haystack/components/converters/multi_file_converter.py b/haystack/components/converters/multi_file_converter.py
index b8145fc29d..bbeadd3d0a 100644
--- a/haystack/components/converters/multi_file_converter.py
+++ b/haystack/components/converters/multi_file_converter.py
@@ -22,7 +22,7 @@
 from haystack.dataclasses import ByteStream
 
 
-class ConverterMimeType(str, Enum):
+class ConverterMimeType(str, Enum):  # noqa: UP042 # StrEnum would change str(), which __init__() parses
     CSV = "text/csv"
     DOCX = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
     HTML = "text/html"
diff --git a/haystack/components/routers/conditional_router.py b/haystack/components/routers/conditional_router.py
index 06d838f3b4..2b7bd8c5e1 100644
--- a/haystack/components/routers/conditional_router.py
+++ b/haystack/components/routers/conditional_router.py
@@ -5,11 +5,10 @@
 import ast
 import contextlib
 from collections.abc import Callable, Mapping, Sequence
-from typing import Any, TypedDict, get_args, get_origin
+from typing import Any, NotRequired, TypedDict, get_args, get_origin
 
 from jinja2 import Environment, TemplateSyntaxError
 from jinja2.nativetypes import NativeEnvironment
-from typing_extensions import NotRequired
 
 from haystack import component, default_from_dict, default_to_dict, logging
 from haystack.core.errors import DeserializationError
diff --git a/haystack/core/pipeline/base.py b/haystack/core/pipeline/base.py
index bf6ecaa1b9..aba5caa322 100644
--- a/haystack/core/pipeline/base.py
+++ b/haystack/core/pipeline/base.py
@@ -10,10 +10,9 @@
 from datetime import datetime
 from enum import IntEnum
 from pathlib import Path
-from typing import Any, TextIO, TypeVar, Union, get_args
+from typing import Any, Self, TextIO, TypeVar, Union, get_args
 
 import networkx
-from typing_extensions import Self
 
 from haystack import logging, tracing
 from haystack.core.component import Component, InputSocket, OutputSocket, component
diff --git a/haystack/core/type_utils.py b/haystack/core/type_utils.py
index 5a3512e1ee..20f116b872 100644
--- a/haystack/core/type_utils.py
+++ b/haystack/core/type_utils.py
@@ -62,9 +62,8 @@ def _resolve_parameter_types(target: Callable, *, include_extras: bool = False)
             # TypeError is raised for objects that cannot carry annotations, NameError for names that are not
             # importable at runtime. Either way we fall back to the unresolved annotations.
             hints = {}
-        # Non-string annotations are kept as they are written: on Python 3.10 `get_type_hints` widens the annotation
-        # of a parameter defaulting to `None` into an optional. This was changed in Python 3.11, see
-        # https://docs.python.org/3/whatsnew/3.11.html#typing.
+        # Non-string annotations are kept as they are written: with `include_extras=False`, `get_type_hints` strips
+        # `Annotated` metadata, which would drop markers such as `Variadic` from annotations that need no resolving.
         return {
             name: hints.get(name, param.annotation) if isinstance(param.annotation, str) else param.annotation
             for name, param in parameters.items()
diff --git a/haystack/dataclasses/chat_message.py b/haystack/dataclasses/chat_message.py
index a9e445db38..37e6772980 100644
--- a/haystack/dataclasses/chat_message.py
+++ b/haystack/dataclasses/chat_message.py
@@ -36,7 +36,7 @@ def _parse_openai_tool_call_arguments(raw_arguments: Any) -> dict[str, Any]:
     return json.loads(raw_arguments) if raw_arguments else {}
 
 
-class ChatRole(str, Enum):
+class ChatRole(str, Enum):  # noqa: UP042 # StrEnum would change str() of this public enum
     """
     Enumeration representing the roles within a chat.
     """
diff --git a/haystack/utils/filters.py b/haystack/utils/filters.py
index 623c78c3b8..695987d954 100644
--- a/haystack/utils/filters.py
+++ b/haystack/utils/filters.py
@@ -91,8 +91,7 @@ def _parse_iso_date(value: str) -> datetime | None:
     try:
         return datetime.fromisoformat(value)
     except ValueError:
-        # Python 3.10's fromisoformat rejects valid ISO 8601 spellings that later versions accept,
-        # most notably a trailing "Z".
+        # fromisoformat still rejects some valid ISO 8601 spellings, such as "24:00" for end-of-day midnight.
         try:
             return dateutil.parser.isoparse(value)
         except (ValueError, OverflowError):
diff --git a/pyproject.toml b/pyproject.toml
index 11a606a89e..c1ccb9171f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ dynamic = ["version"]
 description = "LLM framework to build customizable, production-ready LLM applications. Connect components (models, vector DBs, file converters) to pipelines or agents that can interact with your data."
 readme = "README.md"
 license = "Apache-2.0"
-requires-python = ">=3.10"
+requires-python = ">=3.11"
 authors = [{ name = "deepset.ai", email = "malte.pietsch@deepset.ai" }]
 keywords = [
   "BERT",
@@ -34,11 +34,11 @@ classifiers = [
   "Operating System :: OS Independent",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: 3.14",
+  "Programming Language :: Python :: 3.15",
   "Topic :: Scientific/Engineering :: Artificial Intelligence",
 ]
 dependencies = [
@@ -53,7 +53,6 @@ dependencies = [
   "pyyaml",
   "more-itertools",         # DocumentSplitter
   "networkx",               # Pipeline graphs
-  "typing_extensions>=4.7", # Extended typing features (NotRequired, etc.)
   "httpx",
   "anyio>=4.14.2",          # transitive via httpx and openai; floor for CVE-2026-63374 (GHSA-82r6-8w77-94w6)
   "numpy",
@@ -193,9 +192,9 @@ asyncio_mode = "auto"
 asyncio_default_fixture_loop_scope = "class"
 
 [tool.mypy]
-# Deliberately above the 3.10 floor in `requires-python`: numpy's stubs use PEP 695 `type`
+# Deliberately above the 3.11 floor in `requires-python`: numpy's stubs use PEP 695 `type`
 # statements, which mypy rejects as a syntax error below 3.12. The floor stays covered by the
-# unit test matrix, which runs on 3.10.
+# unit test matrix, which runs on 3.11.
 python_version = "3.12"
 check_untyped_defs = true
 disallow_incomplete_defs = true
diff --git a/releasenotes/notes/drop-python-310-add-python-315-4ec6b40f210a6d61.yaml b/releasenotes/notes/drop-python-310-add-python-315-4ec6b40f210a6d61.yaml
new file mode 100644
index 0000000000..091addec7e
--- /dev/null
+++ b/releasenotes/notes/drop-python-310-add-python-315-4ec6b40f210a6d61.yaml
@@ -0,0 +1,9 @@
+---
+upgrade:
+  - |
+    Dropped support for Python 3.10 since it reaches End of Life (EOL) in October 2026.
+    The minimum supported Python version is now 3.11.
+    If you are on Python 3.10, upgrade your Python version before upgrading Haystack.
+enhancements:
+  - |
+    Haystack now officially supports Python 3.15.
diff --git a/test/core/pipeline/features/test_run.py b/test/core/pipeline/features/test_run.py
index e77a6cfaf0..b8f74f38f6 100644
--- a/test/core/pipeline/features/test_run.py
+++ b/test/core/pipeline/features/test_run.py
@@ -1089,7 +1089,7 @@ def pipeline_that_has_multiple_branches_that_merge_into_a_component_with_a_singl
                     ("add_one_again", 1): {"add": None, "value": 7},
                     ("double", 1): {"value": 3},
                     ("parity", 1): {"value": 3},
-                    ("sum", 1): {"values": [3, 6, 8]},
+                    ("sum", 1): {"values": AnyOrder([3, 6, 8])},
                 },
             ),
         ],
@@ -1751,16 +1751,22 @@ def run(self, query_embedding: list[float]) -> dict[str, list[Document]]:
                     "text_embedder": {
                         "meta": {"model": "mock-model", "usage": {"prompt_tokens": 4, "total_tokens": 4}}
                     },
-                    "joinerfinal": {"documents": [doc1, doc2]},
+                    "joinerfinal": {"documents": AnyOrder([doc1, doc2], key=lambda d: d.id)},
                 },
                 expected_component_calls={
                     ("router", 1): {"query": "I'm a legit question"},
                     ("text_embedder", 1): {"text": "I'm a legit question"},
                     ("bm25retriever", 1): {"query": "I'm a legit question"},
                     ("retriever", 1): {"query_embedding": [1.0, 2.0, 3.0]},
-                    ("joinerhybrid", 1): {"documents": [[doc1], [doc2]], "top_k": None},
-                    ("ranker", 1): {"query": "I'm a legit question", "documents": [doc1, doc2]},
-                    ("joinerfinal", 1): {"documents": [[doc1, doc2]], "top_k": None},
+                    ("joinerhybrid", 1): {
+                        "documents": AnyOrder([[doc1], [doc2]], key=lambda d: d[0].id),
+                        "top_k": None,
+                    },
+                    ("ranker", 1): {
+                        "query": "I'm a legit question",
+                        "documents": AnyOrder([doc1, doc2], key=lambda d: d.id),
+                    },
+                    ("joinerfinal", 1): {"documents": [AnyOrder([doc1, doc2], key=lambda d: d.id)], "top_k": None},
                 },
             ),
             PipelineRunData(
@@ -2260,9 +2266,15 @@ def run(self, create_document: bool = False) -> dict[str, list[Document] | None]
         [
             PipelineRunData(
                 inputs={"first_creator": {"create_document": True}, "third_creator": {"create_document": True}},
-                expected_outputs={"second_creator": {"noop": None}, "documents_joiner": {"documents": [doc1, doc3]}},
+                expected_outputs={
+                    "second_creator": {"noop": None},
+                    "documents_joiner": {"documents": AnyOrder([doc1, doc3], key=lambda d: d.id)},
+                },
                 expected_component_calls={
-                    ("documents_joiner", 1): {"documents": [[doc1], [doc3]], "top_k": None},
+                    ("documents_joiner", 1): {
+                        "documents": AnyOrder([[doc1], [doc3]], key=lambda d: d[0].id),
+                        "top_k": None,
+                    },
                     ("first_creator", 1): {"create_document": True},
                     ("second_creator", 1): {"create_document": False},
                     ("third_creator", 1): {"create_document": True},
@@ -2270,9 +2282,15 @@ def run(self, create_document: bool = False) -> dict[str, list[Document] | None]
             ),
             PipelineRunData(
                 inputs={"first_creator": {"create_document": True}, "second_creator": {"create_document": True}},
-                expected_outputs={"third_creator": {"noop": None}, "documents_joiner": {"documents": [doc1, doc2]}},
+                expected_outputs={
+                    "third_creator": {"noop": None},
+                    "documents_joiner": {"documents": AnyOrder([doc1, doc2], key=lambda d: d.id)},
+                },
                 expected_component_calls={
-                    ("documents_joiner", 1): {"documents": [[doc1], [doc2]], "top_k": None},
+                    ("documents_joiner", 1): {
+                        "documents": AnyOrder([[doc1], [doc2]], key=lambda d: d[0].id),
+                        "top_k": None,
+                    },
                     ("first_creator", 1): {"create_document": True},
                     ("second_creator", 1): {"create_document": True},
                     ("third_creator", 1): {"create_document": False},
@@ -2317,9 +2335,15 @@ def run(self, create_document: bool = False) -> dict[str, list[Document] | None]
         [
             PipelineRunData(
                 inputs={"first_creator": {"create_document": True}, "third_creator": {"create_document": True}},
-                expected_outputs={"second_creator": {"noop": None}, "documents_joiner": {"documents": [doc1, doc3]}},
+                expected_outputs={
+                    "second_creator": {"noop": None},
+                    "documents_joiner": {"documents": AnyOrder([doc1, doc3], key=lambda d: d.id)},
+                },
                 expected_component_calls={
-                    ("documents_joiner", 1): {"documents": [[doc1], [doc3]], "top_k": None},
+                    ("documents_joiner", 1): {
+                        "documents": AnyOrder([[doc1], [doc3]], key=lambda d: d[0].id),
+                        "top_k": None,
+                    },
                     ("first_creator", 1): {"create_document": True},
                     ("second_creator", 1): {"create_document": False},
                     ("third_creator", 1): {"create_document": True},
@@ -2327,9 +2351,15 @@ def run(self, create_document: bool = False) -> dict[str, list[Document] | None]
             ),
             PipelineRunData(
                 inputs={"first_creator": {"create_document": True}, "second_creator": {"create_document": True}},
-                expected_outputs={"third_creator": {"noop": None}, "documents_joiner": {"documents": [doc1, doc2]}},
+                expected_outputs={
+                    "third_creator": {"noop": None},
+                    "documents_joiner": {"documents": AnyOrder([doc1, doc2], key=lambda d: d.id)},
+                },
                 expected_component_calls={
-                    ("documents_joiner", 1): {"documents": [[doc1], [doc2]], "top_k": None},
+                    ("documents_joiner", 1): {
+                        "documents": AnyOrder([[doc1], [doc2]], key=lambda d: d[0].id),
+                        "top_k": None,
+                    },
                     ("first_creator", 1): {"create_document": True},
                     ("second_creator", 1): {"create_document": True},
                     ("third_creator", 1): {"create_document": False},
@@ -2352,6 +2382,8 @@ def that_has_an_answer_joiner_variadic_component():
     query = "What's Natural Language Processing?"
     reply1 = "This is a test answer"
     reply2 = "This is a second test answer"
+    answer1 = GeneratedAnswer(data=reply1, query=query, documents=[], meta={"all_messages": [reply1]})
+    answer2 = GeneratedAnswer(data=reply2, query=query, documents=[], meta={"all_messages": [reply2]})
 
     return (
         pipeline,
@@ -2361,14 +2393,7 @@ def that_has_an_answer_joiner_variadic_component():
                     "answer_builder_1": {"query": query, "replies": [reply1]},
                     "answer_builder_2": {"query": query, "replies": [reply2]},
                 },
-                expected_outputs={
-                    "answer_joiner": {
-                        "answers": [
-                            GeneratedAnswer(data=reply1, query=query, documents=[], meta={"all_messages": [reply1]}),
-                            GeneratedAnswer(data=reply2, query=query, documents=[], meta={"all_messages": [reply2]}),
-                        ]
-                    }
-                },
+                expected_outputs={"answer_joiner": {"answers": AnyOrder([answer1, answer2], key=lambda a: a.data)}},
                 expected_component_calls={
                     ("answer_builder_1", 1): {
                         "documents": None,
@@ -2389,10 +2414,7 @@ def that_has_an_answer_joiner_variadic_component():
                         "replies": [reply2],
                     },
                     ("answer_joiner", 1): {
-                        "answers": [
-                            [GeneratedAnswer(data=reply1, query=query, documents=[], meta={"all_messages": [reply1]})],
-                            [GeneratedAnswer(data=reply2, query=query, documents=[], meta={"all_messages": [reply2]})],
-                        ],
+                        "answers": AnyOrder([[answer1], [answer2]], key=lambda a: a[0].data),
                         "top_k": None,
                     },
                 },
@@ -2845,6 +2867,10 @@ def __init__(self, items, key=None):
     def __eq__(self, other):
         return isinstance(other, list) and sorted(self.items, key=self.key) == sorted(other, key=self.key)
 
+    def __iter__(self):
+        # Lets an AnyOrder be an item of another AnyOrder whose key iterates over its items.
+        return iter(self.items)
+
 
 @given("a pipeline that has a string variadic component", target_fixture="pipeline_data")
 def that_has_a_string_variadic_component():
@@ -4410,7 +4436,9 @@ def pipeline_that_converts_files():
         [
             PipelineRunData(
                 inputs={"router": {"sources": sources}},
-                expected_outputs={"a_joiner": {"documents": expected_csv_docs + expected_splits_docs}},
+                expected_outputs={
+                    "a_joiner": {"documents": AnyOrder(expected_csv_docs + expected_splits_docs, key=lambda d: d.id)}
+                },
                 expected_component_calls={
                     ("router", 1): {"sources": sources, "meta": None},
                     ("csv_converter", 1): {"sources": [sources[0]], "meta": None, "content_column": None},
@@ -4422,9 +4450,12 @@ def pipeline_that_converts_files():
                         ),
                         "top_k": None,
                     },
-                    ("splitter", 1): {"documents": expected_pre_split_docs},
+                    ("splitter", 1): {"documents": AnyOrder(expected_pre_split_docs, key=lambda d: d.id)},
                     ("a_joiner", 1): {
-                        "documents": AnyOrder([expected_csv_docs, expected_splits_docs], key=lambda d: d[0].id),
+                        "documents": AnyOrder(
+                            [expected_csv_docs, AnyOrder(expected_splits_docs, key=lambda d: d.id)],
+                            key=lambda docs: min(d.id for d in docs),
+                        ),
                         "top_k": None,
                     },
                 },
diff --git a/test/test_logging.py b/test/test_logging.py
index 15322a5b99..c8c8408d69 100644
--- a/test/test_logging.py
+++ b/test/test_logging.py
@@ -8,7 +8,7 @@
 import os
 import sys
 from collections.abc import Callable, Generator
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from pathlib import Path
 from unittest.mock import ANY
 
@@ -208,7 +208,7 @@ def test_console_rendered_structured_log(self, capfd: CaptureFixture) -> None:
         output = capfd.readouterr().err
 
         # Only check for the minute to be a bit more robust
-        today = datetime.now(tz=timezone.utc).isoformat(timespec="minutes").replace("+00:00", "")
+        today = datetime.now(tz=UTC).isoformat(timespec="minutes").replace("+00:00", "")
         assert today in output
 
         log_level = "warning"
diff --git a/test/utils/test_filters.py b/test/utils/test_filters.py
index 53d6c566c9..e21d7cc0c9 100644
--- a/test/utils/test_filters.py
+++ b/test/utils/test_filters.py
@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 
 import pytest
 
@@ -132,26 +132,26 @@
         id="> operator with smaller ISO 8601 datetime Document value",
     ),
     pytest.param(
-        {"field": "meta.date", "operator": ">", "value": datetime(2023, 1, 1, tzinfo=timezone.utc)},
+        {"field": "meta.date", "operator": ">", "value": datetime(2023, 1, 1, tzinfo=UTC)},
         Document(meta={"date": "2024-01-01T00:00:00+00:00"}),
         True,
         id="> operator with datetime filter value and ISO 8601 string Document value",
     ),
     pytest.param(
         {"field": "meta.date", "operator": ">", "value": "2023-01-01T00:00:00+00:00"},
-        Document(meta={"date": datetime(2024, 1, 1, tzinfo=timezone.utc)}),
+        Document(meta={"date": datetime(2024, 1, 1, tzinfo=UTC)}),
         True,
         id="> operator with ISO 8601 string filter value and datetime Document value",
     ),
     pytest.param(
-        {"field": "meta.date", "operator": ">", "value": datetime(2023, 1, 1, tzinfo=timezone.utc)},
+        {"field": "meta.date", "operator": ">", "value": datetime(2023, 1, 1, tzinfo=UTC)},
         Document(meta={"date": datetime(2024, 1, 1)}),
         True,
         id="> operator with aware datetime filter value and naive datetime Document value",
     ),
     pytest.param(
         {"field": "meta.date", "operator": ">", "value": datetime(2023, 1, 1)},
-        Document(meta={"date": datetime(2024, 1, 1, tzinfo=timezone.utc)}),
+        Document(meta={"date": datetime(2024, 1, 1, tzinfo=UTC)}),
         True,
         id="> operator with naive datetime filter value and aware datetime Document value",
     ),
@@ -542,13 +542,13 @@
         id="== operator with equal datetime in different ISO 8601 format",
     ),
     pytest.param(
-        {"field": "meta.date", "operator": "==", "value": datetime(2025, 2, 3, 12, 45, 46, tzinfo=timezone.utc)},
+        {"field": "meta.date", "operator": "==", "value": datetime(2025, 2, 3, 12, 45, 46, tzinfo=UTC)},
         Document(meta={"date": "2025-02-03T12:45:46Z"}),
         True,
         id="== operator with datetime filter value and ISO 8601 string Document value",
     ),
     pytest.param(
-        {"field": "meta.date", "operator": "==", "value": datetime(2025, 2, 3, 12, 45, 46, tzinfo=timezone.utc)},
+        {"field": "meta.date", "operator": "==", "value": datetime(2025, 2, 3, 12, 45, 46, tzinfo=UTC)},
         Document(meta={"date": datetime(2025, 2, 3, 12, 45, 46)}),
         True,
         id="== operator with aware datetime filter value and naive datetime Document value",
@@ -651,8 +651,8 @@ def test_document_matches_filter(filters, document, expected_result):
     [
         ("2025-02-03T12:45:46", "2025-02-03T12:45:46+00:00"),
         ("2025-02-03T12:45:46+00:00", "2025-02-03T12:45:46"),
-        (datetime(2025, 2, 3, 12, 45, 46), datetime(2025, 2, 3, 12, 45, 46, tzinfo=timezone.utc)),
-        (datetime(2025, 2, 3, 12, 45, 46, tzinfo=timezone.utc), datetime(2025, 2, 3, 12, 45, 46)),
+        (datetime(2025, 2, 3, 12, 45, 46), datetime(2025, 2, 3, 12, 45, 46, tzinfo=UTC)),
+        (datetime(2025, 2, 3, 12, 45, 46, tzinfo=UTC), datetime(2025, 2, 3, 12, 45, 46)),
     ],
 )
 def test_document_matches_filter_strict_datetime_comparison(operator, expected_result, document_value, filter_value):
diff --git a/test/utils/test_type_serialization.py b/test/utils/test_type_serialization.py
index a8c5a2e626..99e7436d85 100644
--- a/test/utils/test_type_serialization.py
+++ b/test/utils/test_type_serialization.py
@@ -236,10 +236,15 @@ def test_output_type_serialization_typing_generic_with_nonetype():
     assert serialize_type(Dict[type(None), str]) == "typing.Dict[None, str]"  # type: ignore[misc]
     assert serialize_type(Tuple[int, type(None)]) == "typing.Tuple[int, None]"
     assert serialize_type(List[type(None)]) == "typing.List[None]"  # type: ignore[misc]
-    # A Union with more than two members that includes None must keep None as well.
-    assert serialize_type(Union[str, int, None]) == "typing.Union[str, int, None]"
-    # Optional must still be serialized without a redundant trailing None.
-    assert serialize_type(Optional[str]) == "typing.Optional[str]"
+    # A Union with more than two members that includes None must keep None as well, and Optional must still be
+    # serialized without a redundant trailing None.
+    # Python 3.14+ represents typing.Union as types.UnionType, so both serialize with PEP 604 syntax.
+    if sys.version_info >= (3, 14):
+        assert serialize_type(Union[str, int, None]) == "str | int | None"
+        assert serialize_type(Optional[str]) == "str | None"
+    else:
+        assert serialize_type(Union[str, int, None]) == "typing.Union[str, int, None]"
+        assert serialize_type(Optional[str]) == "typing.Optional[str]"
 
 
 def test_output_type_round_trip_typing_generic_with_nonetype():
@@ -266,7 +271,12 @@ def test_output_type_serialization_callable_with_parameter_list():
     assert serialize_type(Callable[[int, str], bool]) == "typing.Callable[[int, str], bool]"
     assert serialize_type(Callable[[], int]) == "typing.Callable[[], int]"
     assert serialize_type(Callable[[int], List[str]]) == "typing.Callable[[int], typing.List[str]]"
-    assert serialize_type(Callable[[Union[str, int]], bool]) == "typing.Callable[[typing.Union[str, int]], bool]"
+    expected = (
+        "typing.Callable[[str | int], bool]"
+        if sys.version_info >= (3, 14)
+        else "typing.Callable[[typing.Union[str, int]], bool]"
+    )
+    assert serialize_type(Callable[[Union[str, int]], bool]) == expected
 
 
 def test_output_type_deserialization_callable_with_parameter_list():