artisan migrate and akin you needed to write a special tunnel config, then open up a tunnel via SSH to your database and then execute those commands locally — using both the tunnel and your special config file. Far from beautiful — we know. It also caused lots of support on our end due to lots of confusion on your end.
From now on
Execute SSH commands directly in your App! This allows you to run
artisan migrate and variations without the need to open up a tunnel first:
ssh email@example.com php artisan migrate
That's of course not all. You can also use tinker-style commands to work directly on your App, utilize task runner such as Envoy to automate reoccurring errands or simply list and check out all your deployed files.
What do I need to change?
Nothing, the old tunnel-way will still work as there are still valid use-cases (eg dump or import your database). Anyhow: now you can migrate with a little more style.
Can I deploy using SSH/SFTP now?
Sorry. This is still not possible, due to the New App infrastructure design: fast, advanced, secure and horizontally scalable. An essential part to make all that possible is the ephemeral storage New Apps come with. So any changes to the file system you make with your remotely executed commands will be lost on a new deploy.