I\'m experimenting with more cost effective ways to deploy my Rails apps, and went through the Ruby Starter Projects to get a feel for Google Cloud Platform.
It\'s al
To turn off the instances associated with older versions you could try to use the teardown scripts (eventually customised) mentioned in the delete tutorial resources doc:
If you tried the tutorial about how to run Ruby on Compute Engine, see the Deployment and teardown scripts section of that tutorial
Careful with deleting the app, though, you can't re-use the app id!
Since the older versions are no longer the default ones at least no new instances will be automatically starting for them. You may still need to delete them manually, unless Google automatically deletes the older automatically assigned versions exceeding the max number of versions allowed for an app.