diff --git a/.github/workflows/_checks.yaml b/.github/workflows/_checks.yaml
index 34814ec5d..e43c3591f 100644
--- a/.github/workflows/_checks.yaml
+++ b/.github/workflows/_checks.yaml
@@ -41,13 +41,13 @@ jobs:
     name: Lint check
     uses: apify/workflows/.github/workflows/python_lint_check.yaml@main
     with:
-      python_versions: '["3.11", "3.12", "3.13", "3.14"]'
+      python_versions: '["3.11", "3.12", "3.13", "3.14", "3.15"]'
 
   type_check:
     name: Type check
     uses: apify/workflows/.github/workflows/python_type_check.yaml@main
     with:
-      python_versions: '["3.11", "3.12", "3.13", "3.14"]'
+      python_versions: '["3.11", "3.12", "3.13", "3.14", "3.15"]'
 
   markdown_lint_check:
     name: Markdown lint check
@@ -135,9 +135,9 @@ jobs:
     uses: apify/workflows/.github/workflows/python_unit_tests.yaml@main
     secrets: inherit
     with:
-      python_versions: '["3.11", "3.12", "3.13", "3.14"]'
+      python_versions: '["3.11", "3.12", "3.13", "3.14", "3.15"]'
       operating_systems: '["ubuntu-latest", "windows-latest"]'
-      python_version_for_codecov: "3.14"
+      python_version_for_codecov: "3.15"
       operating_system_for_codecov: ubuntu-latest
       tests_concurrency: "4"
 
@@ -156,7 +156,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-latest"]
-        python-version: ["3.11", "3.14"]
+        python-version: ["3.11", "3.15"]
 
     runs-on: ${{ matrix.os }}
 
@@ -190,7 +190,7 @@ jobs:
         if: >-
           ${{
             matrix.os == 'ubuntu-latest' &&
-            matrix.python-version == '3.14' &&
+            matrix.python-version == '3.15' &&
             env.CODECOV_TOKEN != ''
           }}
         uses: codecov/codecov-action@303a32d7a59b442fa8d48b6a1cc6825c09c847a5 # v7.1.1
diff --git a/.rules.md b/.rules.md
index 047895dbf..03d582c51 100644
--- a/.rules.md
+++ b/.rules.md
@@ -4,7 +4,7 @@ This file provides guidance to programming agents when working with code in this
 
 ## Project Overview
 
-The Apify SDK for Python (`apify` package on PyPI) is the official library for creating [Apify Actors](https://docs.apify.com/platform/actors) in Python. It provides Actor lifecycle management, storage access (datasets, key-value stores, request queues), event handling, proxy configuration, and pay-per-event charging. It builds on top of the [Crawlee](https://crawlee.dev/python) web scraping framework and the [Apify API Client](https://docs.apify.com/api/client/python). Supports Python 3.11–3.14. Build system: uv_build.
+The Apify SDK for Python (`apify` package on PyPI) is the official library for creating [Apify Actors](https://docs.apify.com/platform/actors) in Python. It provides Actor lifecycle management, storage access (datasets, key-value stores, request queues), event handling, proxy configuration, and pay-per-event charging. It builds on top of the [Crawlee](https://crawlee.dev/python) web scraping framework and the [Apify API Client](https://docs.apify.com/api/client/python). Supports Python 3.11–3.15. Build system: uv_build.
 
 ## Common Commands
 
diff --git a/pyproject.toml b/pyproject.toml
index bfb018bbe..c1fe7feb7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -20,6 +20,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Topic :: Software Development :: Libraries",
     "Typing :: Typed",
 ]
diff --git a/tests/unit/scrapy/extensions/test_httpcache.py b/tests/unit/scrapy/extensions/test_httpcache.py
index f178a13c7..5aa07b0ae 100644
--- a/tests/unit/scrapy/extensions/test_httpcache.py
+++ b/tests/unit/scrapy/extensions/test_httpcache.py
@@ -36,10 +36,13 @@ def test_gzip() -> None:
 
 
 def test_to_gzip() -> None:
-    """`to_gzip` produces the expected gzip-compressed JSON bytes for a fixed mtime."""
+    """`to_gzip` produces gzip-compressed JSON with the given mtime in its header."""
     data_bytes = to_gzip(FIXTURE_DICT, mtime=0)
 
-    assert data_bytes == FIXTURE_BYTES
+    # The header's extra-flags byte and the deflate stream differ across CPython and zlib versions, so
+    # compare the decompressed payload and the mtime.
+    assert gzip.decompress(data_bytes) == gzip.decompress(FIXTURE_BYTES)
+    assert read_gzip_time(data_bytes) == 0
 
 
 def test_from_gzip() -> None: