This site uses different types of cookies, including analytics and functional cookies (its own and from other sites). To change your cookie settings or find out more, click here. If you continue browsing our website, you accept these cookies.
You need to have at least a backup of the 2019.3 mongoDB that works PRIOR to beginning the upgrade. With that, there's a table rename fix that you do in mongoDB at the command line and then you can proceed with the update.
I assume that customer support is providing the detailed instructions once you've opened a support ticket with them, so I won't step on their toes by posting it.