Anypoint Runtime Manager agent now upgrades correctly in the Windows environment.
Mule Upgrade Tool 1.1.1 Release Notes
The Mule upgrade tool is a command line utility for updating and upgrading standalone instances of the Mule 4 runtime engine that are hosted on-premises. The tool can upgrade any supported Mule 4 version (minor, patch, or patch update versions) to a new version.
MuleSoft recommends upgrading to the latest version of Mule.
To incorporate the latest changes and bug fixes, MuleSoft also recommends using the latest version of the tool.