I would start here:

https://docs.automationanywhere.com/bundle/enterprise-v2019/page/enterprise-cloud/topics/deployment-planning/on-prem-install/update-enterprise-a2019.html

If you have further questions, I might start a support ticket or consider contacting our professional services group for assistance.

Thank you so much for sharing the document and for your response. 

We have four Dev servers. On one server, AA360 application is hosted and two servers are using for Development and one server is for bot runner machine. could you please let us know from which server do we need to take backup from.