I think that it would be good to have a switch to put the Universal web interface in maintenance mode, and even better to be able to show messages to users that this is going to happen.
When we do an update and the update, for example recreates the fact table, the update can take a long time. We do send a mailing to the users to warn them that they should not use the application during this time.
It might be better to have a way to lock the users out completely. At this moment I could organize in Azure that users get redirected, but as Universal can still be open in the browsers of users, there is still a risk that users get in a confusing situation.
The ideal scenario would be to have a setting in IAM, which makes that the user gets an “this site is under maintenance” message in the interface, and is prevented from entering data.