This is my current setup:
os1@os1:/usr/local/bin$ minikube update-check
CurrentVersion: v1.20.0
LatestVersion: v1.25.1
os1@os1:/usr/local/bin$ cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 10 (buster)"
What should be the steps to upgrade the minikube?
Minikube is an executable, in this case you would need to re-install the minikube with the desired version. There is no command to upgrade the running Minikube.
You would need to:
sudo minikube delete # remove your minikube cluster
sudo rm -rf ~/.minikube # remove minikube
and reinstall it using Minikube documentation - Start, depends on what your requirements are (packaged used in docs should be always up to date and should cover all your requirements regarding available drivers).