diff --git a/reference/project-testing-interface.rst b/reference/project-testing-interface.rst
index 8e5ca0b2e..736eb709b 100644
--- a/reference/project-testing-interface.rst
+++ b/reference/project-testing-interface.rst
@@ -32,6 +32,14 @@ project:
 Tools and approaches vary by language, please choose which language is
 relevant to you.
 
+.. note::
+
+  Project Testing Interface defines a *minimal* list of platforms that
+  projects should test against. Having a more extensive set of tested platforms
+  (for instance, keeping older platforms that are not yet EOL) is both allowed
+  and encouraged.
+
+
 .. _pti-documentation:
 
 Documentation
diff --git a/reference/pti/python.rst b/reference/pti/python.rst
index 7f8ca33c8..45b498c2d 100644
--- a/reference/pti/python.rst
+++ b/reference/pti/python.rst
@@ -26,11 +26,19 @@ tree:
 - ``sphinx-build -W -b html doc/source doc/build``
 
 The Python 3 version may change from cycle to cycle. Projects should
-target the following, replacing `3x` with the :ref:`tested Python 3 runtimes
-<pti-tested-runtimes>` for the current development cycle:
+target the following, extending supported Python `3x` with the
+:ref:`tested Python 3 runtimes <pti-tested-runtimes>` for the current
+development cycle:
 
 - ``tox -e py3x``
 
+Projects should avoid removing Python versions that have not reached
+`End Of Life <https://devguide.python.org/versions/>`_ without a solid
+reason. It is recommended to keep compatability with older Python versions
+as long as possible.
+While CI coverage of Python versions that are not mentioned in PTI can be reduced,
+such reduction is not mandatory.
+
 Projects that are translated should also support:
 
 - ``tox -e venv python setup.py extract_messages``