$CI->_remove_invisible_characters($str);
fixed to
$CI->input->_remove_invisible_characters($str);
diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index f48bb0b..06375d6 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -136,6 +136,7 @@
<li>Fixed a bug where TRUNCATE was not considered a "write" query (#6619).</li>
<li>Fixed a bug where csv_from_result() was checking for a nonexistent method.</li>
<li>Fixed a bug _protect_identifiers() where it was improperly removing all pipe symbols from items</li>
+ <li>Fixed a fatal error in the Oracle driver (#6752)</li>
</ul>
</li>
<li>Fixed assorted user guide typos or examples (#5998, #6093, #6259, #6339, #6432, #6521).</li>