diff --git a/doc/source/drivers/snmp.rst b/doc/source/drivers/snmp.rst
index a87287b1f6..30ed7efad5 100644
--- a/doc/source/drivers/snmp.rst
+++ b/doc/source/drivers/snmp.rst
@@ -28,6 +28,7 @@ APC              AP7900       Yes           apc_rackpdu
 APC              AP7901       Yes           apc_rackpdu
 APC              AP7902       Yes           apc_rackpdu
 APC              AP7911a      Yes           apc_rackpdu
+APC              AP7921       Yes           apc_rackpdu
 APC              AP7922       Yes           apc_rackpdu
 APC              AP7930       Yes           apc_rackpdu
 APC              AP7931       Yes           apc_rackpdu