diff --git a/reference/filter/filters.xml b/reference/filter/filters.xml
index a3ac07f216..b52ca0027b 100644
--- a/reference/filter/filters.xml
+++ b/reference/filter/filters.xml
@@ -203,6 +203,21 @@
          characters.
         </entry>
        </row>
+       <row>
+        <entry><constant>FILTER_SANITIZE_FULL_SPECIAL_CHARS</constant></entry>
+        <entry>"full_special_chars"</entry>
+        <entry></entry>
+        <entry>
+         <constant>FILTER_FLAG_NO_ENCODE_QUOTES</constant>,
+        </entry>
+        <entry>
+         Equivalent to calling htmlspecialchars with ENT_QUOTES set. Encoding quotes can 
+         be disabled by setting FILTER_FLAG_NO_ENCODE_QUOTES. Like htmlspecialchars(), this
+         filter is aware of the default_charset and if a sequence of bytes is detected that
+         makes up an invalid character in the current character set then the entire string is
+         rejected resulting in a 0-length string.
+        </entry>
+       </row>
        <row>
         <entry><constant>FILTER_SANITIZE_STRING</constant></entry>
         <entry>"string"</entry>