[ci skip] Close #5482

1 files changed, 11 insertions, 0 deletions

diff --git a/user_guide_src/source/installation/upgrade_3110.rst b/user_guide_src/source/installation/upgrade_3110.rst
index a19f1e68e..0e3b7c676 100644
--- a/user_guide_src/source/installation/upgrade_3110.rst
+++ b/user_guide_src/source/installation/upgrade_3110.rst
@@ -12,3 +12,14 @@ Replace all files and directories in your *system/* directory.
 
 .. note:: If you have any custom developed files in these directories,
 	please make copies of them first.
+
+Step 2: 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()`.