deprecation-and-migration

To safely retire legacy code, enforce a replacement-first proof approach and select a migration pattern like Strangler, Adapter, Feature Flag, or Big Bang based on your risk and scope. This prevents downtime and broken dependencies.

Advisory deprecation warns consumers to migrate voluntarily, while compulsory deprecation enforces a strict timeline. The deprecation approach you choose depends on your risk tolerance and the scope of the legacy system being retired.

Clean up Terraform resources by verifying zero active usage and applying safe migration tooling rather than destructive redeployments. This infrastructure-as-code cleanup requires evidence-based justification before removing any resources.

Use a Strangler or Adapter pattern for high-risk, broad-scope migrations to gradually transition consumers. Choose a Big Bang approach for lower-risk scenarios where a rapid, full cutover to the replacement implementation is feasible.

A deprecation announcement must include a concrete timeline, a replacement mapping, and explicit verification steps. Applying guardrails and iron laws prevents feature creep in deprecated code before you confirm zero active usage.

Verify zero active usage by running code usage verification checks and validating evidence-based justification. You must confirm no consumers rely on the zombie dependency before proceeding with compulsory removal.