[ci skip] Update upgrade instructions for PR #5512
diff --git a/user_guide_src/source/installation/upgrade_319.rst b/user_guide_src/source/installation/upgrade_319.rst
index 99a7347..3b8da33 100644
--- a/user_guide_src/source/installation/upgrade_319.rst
+++ b/user_guide_src/source/installation/upgrade_319.rst
@@ -12,3 +12,10 @@
.. note:: If you have any custom developed files in these directories,
please make copies of them first.
+
+********************************
+Step 3: Replace config/mimes.php
+********************************
+
+This config file has received some updates. Please copy it to
+*application/config/mimes.php*.