I saw Tony Bjerstedt speak on feature toggles at the Minnesota Developers Conference.

This talk basically covered the art of making a little branch of our own to develop on and then merging it back into master and was on trunk-based development. "Principles of Product Development Flow" by Donald G. Reinertsen was a book that was namedropped. If you migrate infrastructure from Redis to Memcached (a rival tool) well... better have a branch! As a subtopic Tony Bjerstedt went into toggles and listed four variants:

1. Release Toggles are short-lived and don't change. These allow for early releases of features which can then be shut off again via configuration file changes.
2. Ops Toggles are long-lived and sometimes change. Do load testing to see where the app is cratering and crawling then wall off a potential fail point behind a toggle.
3. Experiment Toggles are short-lived and often change. This is for A/B testing.
4. Permission Toggles are long-lived and often change. This is for premium features.