Node.js v16 reached end-of-life in September 2023 and is no longer receiving security patches. We need to upgrade the runtime to v20 LTS across all environments — development, staging, and production. This will require updating the Dockerfile, CI/CD pipeline configuration, and verifying that all npm dependencies are compatible with v20. Any packages relying on deprecated APIs will need to be replaced or patched before the upgrade can be completed safely.