build(deps): Update to include Python 3.15 and deprecation notice for 3.10

.github/workflows/build-publish.yml

@@ -21,11 +21,11 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
       with:
-          python-version: '3.14'
+          python-version: '3.15'
     - name: Install Poetry
       uses: abatilo/actions-poetry@3765cf608f2d4a72178a9fc5b918668e542b89b1 # v4.0.0
       with:
-        poetry-version: '2.2.1'
+        poetry-version: '2.5.1'
     # The dark mode and light mode Atsign logos in the GitHub README don't
     # show properly on PyPI so we have a copy of the README.md in
     # README.PyPI.md with just the light mode logo.

.github/workflows/python-package.yml

@@ -16,13 +16,13 @@ jobs:
   build:
     # Don't run on PRs from a fork as the secrets aren't available
     if: ${{ github.event.pull_request.head.repo.fork == false }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     timeout-minutes: 15
     strategy:
       max-parallel: 1
       fail-fast: false
       matrix:
-        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15"]
 
     steps:
     - name: Checkout at_python

README.md

@@ -11,6 +11,18 @@
 This repo contains library, samples and examples for developers who wish
 to work with the atPlatform from Python code.
 
+## Python 3.10 deprecation
+
+As of Oct 2026 Python 3.10 is end-of-life, and will no longer receive
+security patches. We have previously
+[decided](https://github.com/atsign-foundation/at_protocol/blob/trunk/decisions/2024-10-python-deprecation.md)
+to continue support for 3.10 for another 6 months (on a best efforts basis).
+From Apr 2027, Python 3.10 will be removeded from the test
+matrix, and pyproject.toml bumped to require Python 3.11.
+
+Older versions of this package will of course remain available on
+[PyPI](https://pypi.org/project/atsdk/), though they may lack features,
+
 ## Getting Started
 
 ### 1. Installation