This release includes a complete redesign of the Dashboard, support for 802.11ac 5GHz access points and several bug fixes. More info is available on the v2.2 release page.
Upgrading your existing RaspAP install to this latest release is very straightforward. See this FAQ for details. Alternatively, you can use the Quick Installer at your Raspberry Pi's shell prompt to (re)install a fresh version:
curl -sL https://install.raspap.com | bash