cPanel & WHM software version 11.40 in the STABLE tier on December 3, 2013.

cPanel & WHM version 11.40 offers support for IPv6 and 1:1 NAT, an API Shell, and more.

IPv6 Support
cPanel & WHM is now IPv6-enabled with dual-stack support, allowing customers to add IPv6 or IPv4 to any account. This feature prepares our customers for future demand.

1:1 NAT Support
cPanel & WHM version 11.40 provides 1:1 NAT, giving customers the ability to support a broader range of hosting environments.

API Shell
In 11.40, cPanel & WHM includes an API Shell, enabling customers to run and troubleshoot API calls interactively through the cPanel & WHM user interfaces. This feature helps our customers better understand API calls.