Storage with octoprint in docker

Hi all

I need to upgrade an old octoprint install running on an old OS etc, so I thought perhaps to dockerise it. I just wonder what'll happen to storage if I do. The 'old and proven way' of upgrading a docker images is to remove it and install a new one - fine - but I want to keep my data. Is this problematic with docker? If so, I guess I'll stick to the old way by manually installing