Unfortunately, not everyone will be able to use canary deployments. There are some cases in which we won’t be able to use the strategy:

When working in environments that won’t allow any type of continuous deployments, like in the medical or aerospace industries.

When we’re dealing with mission-critical or life-supporting systems, like applications for energy grids or nuclear reactors.

When a failure has disastrous economic consequences, like on financial systems.

When we need to do breaking schema changes in the database or the storage backend.

When we depend on the software installed on the user’s computers and have no way of updating it remotely.