[ci skip] Add changelog entry for PR #4780
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 97b4d25..aa9af21 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -22,6 +22,7 @@
- Fixed a bug (#4759) - :doc:`Form Validation <libraries/form_validation>`, :doc:`Trackback <libraries/trackback>` and `XML-RPC <libraries/xmlrpc>` libraries treated URI schemes in a case-sensitive manner.
- Fixed a bug (#4762) - :doc:`Cache Library <libraries/caching>` 'file' driver method ``get_metadata()`` checked TTL time against ``mtime`` instead of the cache item's creation time.
- Fixed a bug where :doc:`File Uploading Library <libraries/file_uploading>` generated error messages on PHP 7.1.
+- Fixed a bug (#4780) - :doc:`compatibility function <general/compatibility_functions>` ``hex2bin()`` didn't reject inputs of type "resource".
Version 3.1.0
=============