DNN upgrade steps:
1.First download the upgrade version of the DNN platform from one of these websites:
https://www.dnnsoftware.com/community/download
https://github.com/dnnsoftware/Dnn.Platform/releases/tag/v9.13.0
2.Upload the upgrade file in the path of the website folder (default httpdocs folder) or the folder with the subdomain name. Be sure to check the box to replace similar files extracting the platform file in the folder you uploaded (make sure there is no existing file in it).
3.Enter the domain in the browser and upgrade DNN according to the video.