In ArcGIS Portal, If we have an option to add application wise outage notice so that message is displayed only for those applications which will be impacted during maintenance schedule .
In Current 10.8.1, we can enable information banner at Portal level only but if we have this functionality added for all types of application of Portal like web application, dashboards etc then that will be more useful.
For example, if we are planning to do some maintenance work on one business application then we can display that outage notice at bottom of that application as a reminder to user about the upcoming maintenance and its impact.
