Before upgrading, please ensure the machine hosting Loome Publish is running version 4.6.2 or above of the .net framework.
You can find steps to check the version number here - https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/how-to-determine-which-versions-are-installed#to-find-net-framework-versions-by-viewing-the-registry-net-framework-45-and-later
You can find dot net framework downloads here - https://dotnet.microsoft.com/download/dotnet-framework-runtime
Once completed, follow the steps under Running the Upgrade to install your upgrade.