You can update from version to version!
Check the available versions here:
mailcow/mailcow-dockerizedreleases
Then, for example, check out the version released after your current version
git checkout 2025-02
Run this command in the Mailcow directory, run update.sh, and check if everything is working. Then move on to the next version, and so on.
If everything worked out and you are running 2025-09b you have to checkout the master branch again
git checkout master