Post: Drop support for MkDocs 0.17.3

Announcement of readthedocs/readthedocs.org#10584

drop-support-for-mkdocs-0-17-3.rst

@@ -0,0 +1,36 @@
+.. post:: August 2, 2023
+   :tags: builders
+   :author: Manuel
+   :location: BCN
+   :category: Changelog
+
+Drop support for MkDocs 0.17.3
+==============================
+
+Historically, Read the Docs has installed MkDocs ``0.17.3`` by default if the project didn't define a specific version of it.
+Now, this version is a pretty old and we recommend our users to use the latest version of MkDocs. Currently, ``1.5.1``.
+
+To avoid failing builds of projects using the version installed by default if we upgrade to the latest MkDocs version available,
+we kept installing the old one during all this time.
+Now, *we are changing that behavior to always install the latest available version* and we wanted to let you know about that so you can prepare your project.
+
+**Starting on September 5th Read the Docs will install the latest available version of MkDocs**.
+If you want to use a different version, make sure you are pinning your MkDocs dependency.
+
+Here you have a pretty simple example of the section required on the `.readthedocs.yaml` configuration file:
+
+.. code-block:: yaml
+
+   # ... snip ...
+
+   python:
+     install:
+       - requirements: docs/requirements.txt
+
+   # ... snip ...
+
+The content of `docs/requirements.txt` would be similar to::
+
+  mkdocs==1.5.1
+
+Read more about this in our `Reproducible builds <https://docs.readthedocs.io/en/stable/guides/reproducible-builds.html>`_ guide for more details.