Changed the behaviour of custom callbacks so that they no longer trigger the "required" rule.
diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index d9819d4..69e4614 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -76,7 +76,8 @@
<li>Added a check for NULL fields in the MySQL database backup utility.</li>
<li>Documented the timezones() function in the <a href="./helpers/date_helper.html">Date Helper</a>.</li>
<li>Documented unset_userdata in the <a href="./libraries/sessions.html">Session class</a>.</li>
- <li>Fixed a bug in <a href="./libraries/validation.html">Validation</a> where valid_ip() wasn't called properly</li>
+ <li>Changed the behaviour of custom callbacks so that they no longer trigger the "required" rule. </li>
+ <li>Fixed a bug in <a href="./libraries/validation.html">Validation</a> where valid_ip() wasn't called properly.</li>
<li>Fixed a bug in the Session library where user agent matching would fail on user agents ending with a space. </li>
<li>Fixed a bug in database driver where num_rows property wasn't getting updated.</li>
<li>Fixed a bug in captcha calling an invalid PHP function.</li>