[ci skip] Deprecate prep_for_form() in Form_validation
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index de488a9..e88b68f 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -10,6 +10,7 @@
 -  General Changes
 
    -  Added a destructor to :doc:`Cache Library <libraries/caching>` 'memcached' driver to ensure that Memcache(d) connections are properly closed.
+   -  Deprecated :doc:`Form Validation Library <libraries/form_validation>` method ``prep_for_form()``.
 
 Bug fixes for 3.0.6
 -------------------