[lukeholder]

I work on a PHP project that is installed an any number of environments - so exactly duplicating production is impossible. Of course we have a CI/Test system that tests various combinations of PHP version and DB engines, but we can't replicate every possible production environment. Using Docker to match production is therefore moot in our case.

All the PHP development frameworks these days have moved to Docker or VMs but nothing beats native. Indigo looks promising.

[JeffMarmalade]

Interesting! I hope Indigo may be really helpful for you. If I'm understanding your use-case correctly, you could create a stack with both MySQL versions, and another stack containing a site per PHP version, all pointing at the same codebase in your filesystem, but each configured to use a different PHP. Then you can run them all simultaneously if you want, with each in their own browser window eg project-72.test, project-73.test, project-74.test, project-80.test etc (one per PHP).