Add a compatibility note for the 'ldap' function.
[skip ci]
@@ -599,7 +599,8 @@ DIGIT ::= &lt;any US-ASCII digit "0".."9"&gt;
regular file)</td><td>restricted</td></tr>
<tr><td><code>ldap</code></td>
<td>Escape characters as required by LDAP distinguished name escaping
- (RFC4514) and LDAP filter escaping (RFC4515).</td><td></td></tr>
+ (RFC4514) and LDAP filter escaping (RFC4515).<br />
+ (Available in httpd 2.4.53 and later)</td><td></td></tr>
<tr><td><code>replace</code></td>
<td>replace(string, "from", "to") replaces all occurrences of "from"
in the string with "to". The first parameter must not be a literal string.
