Dear community,
I am struggling with the following topic:
We have an ECE cluster with 3.6.2 running on Ubuntu 20.04.6 LTS and Docker 20.10.24.
As it is suggested here the Docker versions are pinned:
echo "docker-ce hold" | sudo dpkg --set-selections
echo "docker-ce-cli hold" | sudo dpkg --set-selections
echo "containerd.io hold" | sudo dpkg --set-selections
So the currently installed and pinned packages needed for ECE 3.6 are:
docker-ce/focal,now 5:20.10.24~3-0~ubuntu-focal amd64
docker-ce-cli/focal,now 5:20.10.24~3-0~ubuntu-focal amd64
containerd.io/focal,now 1.6.21-1 amd64
Now ECE 3.7.1 is out and we would like to upgrade. But as it is written in the official release notes:
Ubuntu 20.04, SLES 12, and SLES 15 with Docker < 24.0 are no longer supported. They are now only supported with Docker 24.0.
So we need to upgrade our Docker first! Also the release notes say, that
Ubuntu 18.04 is no longer supported.
Well, we have currently Ubuntu 20.04, but it is totally possible, that with the next major ECE version it will not be supported as well. So we would like to upgrade our Docker and our Ubuntu to be better prepared for the future.
Now now to my main issue:
How to do the upgrade of Docker and ECE and also Ubuntu?
I think, the ECE service can be stopped and then Docker can be upgraded. But will the ECE Upgrade script work then?
bash <(curl -fsSL https://download.elastic.co/cloud/elastic-cloud-enterprise.sh) upgrade
Will an upgraded Docker version from 20.10 to 24.0 not completed break ECE 3.6?
So I am now really struggling with the correct order of the upgrade steps 
Is there probably a How-To-Do for that? All I have found till now are HTDs for a clean install of ECE 3.7 and the needed software prerequisites for it. But how to do the upgrade with outdated prerequisites and the fact, that the current ECE 3.6 will not work with the Docker version needed for ECE 3.7.
It is now a classic "Chicken and egg problem" for me
If there are some HTDs, then a link to that would greatly help.
Thank you kindly in advance!