How to restore the Kiwi TCMS to earlier version after upgraded to latest

I have been running Kiwi TCMS as a Docker container, the version running is 9.0.1. Now I have seen the latest version 10.0, so like to update it. Not sure this will not break the existing data.

So, I have taken the database and uploads files backup by following it, https://kiwitcms.org/blog/atodorov/2018/07/30/how-to-backup-docker-volumes-for-kiwi-tcms/

But, how can I downgrade to an older version image, if the latest version does not work as expected or any problem comes? I found the docker tag concept and not sure how to apply it?

Can you confirm following will restore to an older version?

Restore the DB files and uploaded files that already taken backup.
Change the image in docker-compose file to an older one? Like my case, I could want to pull the version 9.0.1 image, so changing the image: kiwitcms/kiwi:9.0.1 works?

web:
    container_name: kiwi_web
    depends_on:
        - db
    restart: always
    image: kiwitcms/kiwi:9.0.1

Or how should I tag version 9.0.1, and then restore the tagged version, in case of reverting the latest upgrade?

Solution

But, how can I downgrade to an older version image, if the latest version does not work as expected or any problem comes? I found the docker tag concept and not sure how to apply it?

The easiest way would be to destroy the instance you were not happy with, start a new one (with v9.0.1) from scratch and restore the files/DB from your backup. I am assuming you made the backup before the upgrade.

image: kiwitcms/kiwi:9.0.1 works?

In theory that would work but in practice it won't because Kiwi TCMS upstream doesn't ship version tagged container images. See https://kiwitcms.org/#subscriptions, lines Only latest releases vs. Versioned releases from kiwitcms/version.

Or how should I tag version 9.0.1

Depending on what you've already done or not done this could either be possible or not possible:

Execute docker images and if you see something like

kiwitcms/kiwi                                              latest    9f23186803d5   8 weeks ago     736MB
kiwitcms/kiwi                                              <no tag>    <another image hash>   ...

this means that latest points to v10 while the untagged image is your previous image, 9.0.1 in your case. You can then use docker tag command to tag it and make use of it inside docker-compose.yml file.

If you only see a kiwitcms/kiwi:latest image this means you have removed the previous one from your system. You don't have access to it. Your options are:
1. Rebuild that from source using the same git tag or
2. Purchase a subscription to be able to access the private kiwitcms/version repository if it is critical to restore back to the old version.

As a good practice you can follow these 2 advices:

Use the "restore-from-backup" technique or maybe "clone the docker image" so that you are upgrading and experimenting with a different Kiwi TCMS instance, not the main one that you use. If you are happy with the latest version then you can upgrade the main instance. Note here that by "clone the docker image" I mean make the running image/container files available on a different machine or possibly the same host machine but launch a secondary Kiwi TCMS instance + a secondary DB. ATM I'm not sure how exactly to do this but either docker itself or other Linux tools should be able to help here.
docker tag your local kiwitcms/kiwi images when you download/deploy/upgrade them so that you can have a reference to the version at this point in time. This will avoid losing the older image.
Extra tip: with docker tag you can also provide your own customized image names and possibly upload these images to your own docker repository for later access/backup or distributing them between multiple host systems.