I haven't tried adding it to an "older" version of rails. It does seem to be fairly decoupled from Rails as its own gem. Though, one weird thing that they do which is a little strange that could prevent this from easily working is in the ActiveStorage gemspec. ```ruby s.add_dependency "actionpack", version s.add_dependency "activerecord", version ``` It has this reference to version which is in the main branch's `RAILS_VERSION` file. If you reference a `5.1.6` tag, the ActiveStorage gem wouldn't exist. You may need to clone the repo and manually adjust it. This would inherently add a level of technical debt as you would have to migrate any bugfixes/security patches/enhancements to your branch.