add link to compatibility matrix
Upgrade Guide
=============
-This is a list of changes introduced in each release that users should be aware of when migrating from older versions.
+This page covers changes introduced in each major version that users should know when migrating from older releases.
+Please see also the :ref:`compatibility_matrix` for supported environments of each major version.
CuPy v10
========
@@ -362,6 +363,8 @@ For performance reasons, :func:`cupy.count_nonzero` has been changed to return z
See the discussion in `#154 <https://github.com/cupy/cupy/pull/154>`_ for more details.
+.. _compatibility_matrix:
+
Compatibility Matrix
====================
