diff --git a/reference/openssl/functions/openssl-csr-sign.xml b/reference/openssl/functions/openssl-csr-sign.xml
index 89c06a92c022..607f5a0ffe24 100644
--- a/reference/openssl/functions/openssl-csr-sign.xml
+++ b/reference/openssl/functions/openssl-csr-sign.xml
@@ -86,6 +86,18 @@
       </para>
      </listitem>
     </varlistentry>
+    <varlistentry>
+     <term><parameter>serial_hex</parameter></term>
+     <listitem>
+      <para>
+       An optional hexadecimal string representing the serial number of the
+       issued certificate. If set, it takes precedence over the
+       <parameter>serial</parameter> parameter value. If not specified or set
+       to &null;, the <parameter>serial</parameter> parameter value is used
+       instead.
+      </para>
+     </listitem>
+    </varlistentry>
    </variablelist>
   </para>
  </refsect1>
@@ -108,6 +120,12 @@
      </row>
     </thead>
     <tbody>
+     <row>
+      <entry>8.4.0</entry>
+      <entry>
+       The <parameter>serial_hex</parameter> parameter is added.
+      </entry>
+     </row>
      <row>
       <entry>8.0.0</entry>
       <entry>