Merge pull request #1563 from vlakoff/doc
Document in the 3.0.0 upgrade guide a breaking change in Array Helper
diff --git a/user_guide_src/source/installation/upgrade_300.rst b/user_guide_src/source/installation/upgrade_300.rst
index 1419909..676c99e 100644
--- a/user_guide_src/source/installation/upgrade_300.rst
+++ b/user_guide_src/source/installation/upgrade_300.rst
@@ -45,4 +45,10 @@
Step 5: Move your errors folder
===============================
-In version 3.0.0, the errors folder has been moved from _application/errors* to _application/views/errors*.
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+In version 3.0.0, the errors folder has been moved from _application/errors* to _application/views/errors*.
+
+Step 6: Check the calls to Array Helper's element() and elements() functions
+============================================================================
+
+The default return value of these functions, when the required elements
+don't exist, has been changed from FALSE to NULL.
\ No newline at end of file