Suggestion
Before installing a new build, it's a good practice to backup database and website since DNN doesn't provide a built-in mechanism to roll back.
Important
Install each successive stable version. For example, do not advance directly from version 5.18.X to 5.21.X, as it may result in site errors. Instead, install 5.19.X, 5.20.X, and then 5.21.X.
