Currently, OOTB Znode does not have a maintenance mode in place. If you are looking to put up a public-facing temporary maintenance page for the Webstore, then we can suggest an alternative approach, further details are below.

As an alternative workaround, the most sustainable approach is to simply put a maintenance HTML page in IIS in replacement of the Znode webstore application. For this approach, we would recommend utilizing a simple HTML page (some examples), which includes the maintenance communication of your choice. This HTML page will then be configured through IIS, (which powers the Znode applications at the server level) to replace the Webstore application (Znode.Engine.WebStore)