[ci skip] Close #5482

1 files changed, 11 insertions, 0 deletions

diff --git a/user_guide_src/source/installation/upgrade_320.rst b/user_guide_src/source/installation/upgrade_320.rst
index 3eadd8caf..a9dc274c7 100644
--- a/user_guide_src/source/installation/upgrade_320.rst
+++ b/user_guide_src/source/installation/upgrade_320.rst
@@ -257,3 +257,14 @@ so that if you're using the :doc:`Web Page Caching <../general/caching>`
 feature, you'll be left with some old, garbage cache files.
 
 That shouldn't be a problem, but you may want to clear them.
+
+Step 13: Check for calls to is_countable()
+==========================================
+
+
+PHP 7.3 introduces a native `is_countable() <https://secure.php.net/is_countable>`_
+function, which creates a name collision with the ``is_countable()`` function
+we've had in our :doc:`Inflector Helpers <../helpers/inflector_helper>`.
+
+If you've been using the helper function in question, you should now rename
+the calls to it to :php:func:`word_is_countable()`.